diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9a11b3b59..fc6f3c895 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -386,9 +386,9 @@ If(WANT_GIG)
 ENDIF(WANT_GIG)
 
 # check for pthreads
-IF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE)
+IF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE OR LMMS_BUILD_OPENBSD)
 	FIND_PACKAGE(Threads)
-ENDIF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE)
+ENDIF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE OR LMMS_BUILD_OPENBSD)
 
 # check for WINE
 IF(WANT_VST)
diff --git a/cmake/modules/DetectMachine.cmake b/cmake/modules/DetectMachine.cmake
index c0d6cba34..b5fb573fd 100644
--- a/cmake/modules/DetectMachine.cmake
+++ b/cmake/modules/DetectMachine.cmake
@@ -2,6 +2,8 @@ IF(WIN32)
 	SET(LMMS_BUILD_WIN32 1)
 ELSEIF(APPLE)
 	SET(LMMS_BUILD_APPLE 1)
+ELSEIF(${CMAKE_SYSTEM_NAME} MATCHES "OpenBSD")
+    SET(LMMS_BUILD_OPENBSD 1)
 ELSEIF(HAIKU)
 	SET(LMMS_BUILD_HAIKU 1)
 ELSE()
diff --git a/include/lmms_math.h b/include/lmms_math.h
index b4d8995a0..28a3ce863 100644
--- a/include/lmms_math.h
+++ b/include/lmms_math.h
@@ -34,7 +34,7 @@
 #include <cmath>
 using namespace std;
 
-#if defined (LMMS_BUILD_WIN32) || defined (LMMS_BUILD_APPLE) || defined(LMMS_BUILD_HAIKU)  || defined (__FreeBSD__)
+#if defined (LMMS_BUILD_WIN32) || defined (LMMS_BUILD_APPLE) || defined(LMMS_BUILD_HAIKU)  || defined (__FreeBSD__) || defined(__OpenBSD__)
 #ifndef isnanf
 #define isnanf(x)	isnan(x)
 #endif
diff --git a/include/versioninfo.h b/include/versioninfo.h
index 58f7a79e9..8477a61c0 100644
--- a/include/versioninfo.h
+++ b/include/versioninfo.h
@@ -24,6 +24,10 @@
 #define PLATFORM "OS X"
 #endif
 
+#ifdef LMMS_BUILD_OPENBSD
+#define PLATFORM "OpenBSD"
+#endif
+
 #ifdef LMMS_BUILD_WIN32
 #define PLATFORM "win32"
 #endif
diff --git a/plugins/LadspaEffect/calf/CMakeLists.txt b/plugins/LadspaEffect/calf/CMakeLists.txt
index 3bd4ae0f8..02e8a2d93 100644
--- a/plugins/LadspaEffect/calf/CMakeLists.txt
+++ b/plugins/LadspaEffect/calf/CMakeLists.txt
@@ -15,7 +15,7 @@ SET_TARGET_PROPERTIES(calf PROPERTIES COMPILE_FLAGS "-O2 -finline-functions ${IN
 IF(LMMS_BUILD_WIN32)
 	ADD_CUSTOM_COMMAND(TARGET calf POST_BUILD COMMAND "${STRIP}" "$<TARGET_FILE:calf>")
 ENDIF(LMMS_BUILD_WIN32)
-IF(NOT LMMS_BUILD_APPLE)
+IF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 	SET_TARGET_PROPERTIES(calf PROPERTIES LINK_FLAGS "${LINK_FLAGS} -shared -Wl,-no-undefined")
-ENDIF(NOT LMMS_BUILD_APPLE)
+ENDIF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 
diff --git a/plugins/LadspaEffect/caps/CMakeLists.txt b/plugins/LadspaEffect/caps/CMakeLists.txt
index cb4ce1a00..eb9c6f7eb 100644
--- a/plugins/LadspaEffect/caps/CMakeLists.txt
+++ b/plugins/LadspaEffect/caps/CMakeLists.txt
@@ -11,9 +11,9 @@ SET_TARGET_PROPERTIES(caps PROPERTIES COMPILE_FLAGS "-O2 -funroll-loops -Wno-wri
 IF(LMMS_BUILD_WIN32)
 	ADD_CUSTOM_COMMAND(TARGET caps POST_BUILD COMMAND "${STRIP}" \"$<TARGET_FILE:caps>\")
 ENDIF(LMMS_BUILD_WIN32)
-IF(NOT LMMS_BUILD_APPLE)
+IF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 	SET_TARGET_PROPERTIES(caps PROPERTIES LINK_FLAGS "${LINK_FLAGS} -shared -Wl,-no-undefined")
-ENDIF(NOT LMMS_BUILD_APPLE)
+ENDIF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 
 IF(LMMS_BUILD_LINUX)
 	SET_TARGET_PROPERTIES(caps PROPERTIES LINK_FLAGS "${LINK_FLAGS}")
diff --git a/plugins/LadspaEffect/cmt/CMakeLists.txt b/plugins/LadspaEffect/cmt/CMakeLists.txt
index 81bb13dc2..cb48b414d 100644
--- a/plugins/LadspaEffect/cmt/CMakeLists.txt
+++ b/plugins/LadspaEffect/cmt/CMakeLists.txt
@@ -12,7 +12,7 @@ ELSE(LMMS_BUILD_WIN32)
 	SET_TARGET_PROPERTIES(cmt PROPERTIES COMPILE_FLAGS "${COMPILE_FLAGS} -fPIC")
 ENDIF(LMMS_BUILD_WIN32)
 
-IF(NOT LMMS_BUILD_APPLE)
+IF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 	SET_TARGET_PROPERTIES(cmt PROPERTIES LINK_FLAGS "${LINK_FLAGS} -shared -Wl,-no-undefined")
-ENDIF(NOT LMMS_BUILD_APPLE)
+ENDIF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 
diff --git a/plugins/LadspaEffect/swh/CMakeLists.txt b/plugins/LadspaEffect/swh/CMakeLists.txt
index e140b1793..fb203c6da 100644
--- a/plugins/LadspaEffect/swh/CMakeLists.txt
+++ b/plugins/LadspaEffect/swh/CMakeLists.txt
@@ -21,7 +21,7 @@ FOREACH(_item ${PLUGIN_SOURCES})
 	ENDIF(LMMS_BUILD_WIN32)
 	IF(LMMS_BUILD_APPLE)
 		SET_TARGET_PROPERTIES("${_plugin}" PROPERTIES LINK_FLAGS "${LINK_FLAGS} -Bsymbolic -lm")
-	ELSE(LMMS_BUILD_APPLE)
+	ELSEIF(NOT LMMS_BUILD_APPLE AND NOT LMMS_BUILD_OPENBSD)
 		SET_TARGET_PROPERTIES("${_plugin}" PROPERTIES LINK_FLAGS "${LINK_FLAGS} -shared -Wl,-no-undefined -Wl,-Bsymbolic -lm")
 	ENDIF(LMMS_BUILD_APPLE)
 	IF(LMMS_BUILD_LINUX OR LMMS_BUILD_HAIKU)
diff --git a/plugins/LadspaEffect/tap/CMakeLists.txt b/plugins/LadspaEffect/tap/CMakeLists.txt
index 499dbf046..b8d451e6d 100644
--- a/plugins/LadspaEffect/tap/CMakeLists.txt
+++ b/plugins/LadspaEffect/tap/CMakeLists.txt
@@ -11,7 +11,7 @@ FOREACH(_item ${PLUGIN_SOURCES})
 	ENDIF(LMMS_BUILD_WIN32)
 	IF(LMMS_BUILD_APPLE)
 		SET_TARGET_PROPERTIES("${_plugin}" PROPERTIES LINK_FLAGS "${LINK_FLAGS} -Bsymbolic -lm")
-	ELSE(LMMS_BUILD_APPLE)
+	ELSEIF(NOT LMMS_BUILD_OPENBSD)
 		SET_TARGET_PROPERTIES("${_plugin}" PROPERTIES LINK_FLAGS "${LINK_FLAGS} -shared -Wl,-no-undefined -Wl,-Bsymbolic -lm")
 	ENDIF(LMMS_BUILD_APPLE)
 	IF(LMMS_BUILD_LINUX OR LMMS_BUILD_HAIKU)
diff --git a/plugins/zynaddsubfx/CMakeLists.txt b/plugins/zynaddsubfx/CMakeLists.txt
index fa96b9f32..b550db6e2 100644
--- a/plugins/zynaddsubfx/CMakeLists.txt
+++ b/plugins/zynaddsubfx/CMakeLists.txt
@@ -2,11 +2,13 @@ INCLUDE(BuildPlugin)
 
 
 # definitions for ZynAddSubFX
-IF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE)
+IF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE OR LMMS_BUILD_OPENBSD)
+	FIND_PACKAGE(X11)
+	INCLUDE_DIRECTORIES(${X11_INCLUDE_DIR})
 	ADD_DEFINITIONS(-DOS_LINUX)
-ELSE(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE)
+ELSE()
 	ADD_DEFINITIONS(-DOS_WINDOWS)
-ENDIF(LMMS_BUILD_LINUX OR LMMS_BUILD_APPLE)
+ENDIF()
 
 # do not conflict with LMMS' Controller class
 ADD_DEFINITIONS(-DController=ZynController)
diff --git a/plugins/zynaddsubfx/zynaddsubfx/src/Misc/Util.h b/plugins/zynaddsubfx/zynaddsubfx/src/Misc/Util.h
index 45d6f84fc..0e67f0367 100644
--- a/plugins/zynaddsubfx/zynaddsubfx/src/Misc/Util.h
+++ b/plugins/zynaddsubfx/zynaddsubfx/src/Misc/Util.h
@@ -104,7 +104,9 @@ inline void sprng(prng_t p)
 /*
  * The random generator (0.0f..1.0f)
  */
+#ifndef  INT32_MAX
 # define INT32_MAX      (2147483647)
+#endif
 #define RND (prng() / (INT32_MAX * 1.0f))
 
 //Linear Interpolation
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4d1a4a60d..0a1388de3 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -106,6 +106,10 @@ IF(LMMS_BUILD_APPLE)
 	SET(EXTRA_LIBRARIES "-framework CoreMIDI")
 ENDIF()
 
+if(LMMS_HAVE_OSS AND LMMS_BUILD_OPENBSD)
+    SET(EXTRA_LIBRARIES "-lossaudio")
+endif()
+
 SET(LMMS_REQUIRED_LIBS
 	${CMAKE_THREAD_LIBS_INIT}
 	${QT_LIBRARIES}
diff --git a/src/lmmsconfig.h.in b/src/lmmsconfig.h.in
index 3d48d8372..9fcdfc176 100644
--- a/src/lmmsconfig.h.in
+++ b/src/lmmsconfig.h.in
@@ -2,6 +2,7 @@
 #cmakedefine LMMS_BUILD_WIN32
 #cmakedefine LMMS_BUILD_WIN64
 #cmakedefine LMMS_BUILD_APPLE
+#cmakedefine LMMS_BUILD_OPENBSD
 #cmakedefine LMMS_BUILD_HAIKU
 
 #cmakedefine LMMS_HOST_X86