diff --git a/sys/sys/elf.h b/sys/sys/elf.h
index 54df9336ab9c..b2d6b77c98e2 100644
--- a/sys/sys/elf.h
+++ b/sys/sys/elf.h
@@ -38,8 +38,4 @@
 #include <sys/elf32.h>
 #include <sys/elf64.h>
 
-#ifdef _SOLARIS_C_SOURCE
-#include <sys/_elf_solaris.h>
-#endif
-
 #endif /* !_SYS_ELF_H_ */
diff --git a/sys/sys/kernel.h b/sys/sys/kernel.h
index f9f1889d2775..c278dc4f76ae 100644
--- a/sys/sys/kernel.h
+++ b/sys/sys/kernel.h
@@ -68,9 +68,7 @@ extern int stathz;			/* statistics clock's frequency */
 extern int profhz;			/* profiling clock's frequency */
 extern int profprocs;			/* number of process's profiling */
 extern int ticks;
-#ifndef _SOLARIS_C_SOURCE
 extern int lbolt;			/* once a second sleep address */
-#endif
 
 #endif /* _KERNEL */
 
diff --git a/sys/sys/param.h b/sys/sys/param.h
index 5c043169a080..ba3658af771d 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -303,20 +303,4 @@ __END_DECLS
 #define ctodb(db)			/* calculates pages to devblks */ \
 	((db) << (PAGE_SHIFT - DEV_BSHIFT))
 
-/*
- * Solaris compatibility definitions.
- */
-#ifdef _SOLARIS_C_SOURCE
-#define	PAGESIZE	PAGE_SIZE
-
-/*
- * The OpenSolaris version is set according to the version last imported
- * from http://dlc.sun.com/osol/on/downloads/current/. In FreeBSD header
- * files it can be used to determine the level of compatibility that the
- * FreeBSD headers provide to OpenSolaris code. Perhaps one day there
- * will be a really, really Single Unix Specification.
- */
-#define __OpenSolaris_version 20060731
-#endif
-
 #endif	/* _SYS_PARAM_H_ */
diff --git a/sys/sys/stat.h b/sys/sys/stat.h
index d3572c34e0ea..10a3739cc440 100644
--- a/sys/sys/stat.h
+++ b/sys/sys/stat.h
@@ -304,14 +304,6 @@ struct nstat {
 
 #endif /* __BSD_VISIBLE */
 
-/*
- * Solaris compatibility definitions.
- */
-#ifdef _SOLARIS_C_SOURCE
-#define	stat64	stat
-#define	fstat64	fstat
-#endif
-
 #ifndef _KERNEL
 __BEGIN_DECLS
 #if __BSD_VISIBLE
diff --git a/sys/sys/time.h b/sys/sys/time.h
index 0350c203eeb9..bef778752bcd 100644
--- a/sys/sys/time.h
+++ b/sys/sys/time.h
@@ -324,27 +324,4 @@ __END_DECLS
 
 #endif /* !_KERNEL */
 
-/*
- * Solaris compatibility definitions.
- */
-#ifdef _SOLARIS_C_SOURCE
-/*
- *  Definitions for commonly used resolutions.
- */
-#define SEC		1
-#define MILLISEC	1000
-#define MICROSEC	1000000
-#define NANOSEC		1000000000
-
-typedef longlong_t	hrtime_t;
-
-#ifndef _KERNEL
-static __inline hrtime_t gethrtime(void) {
-	struct timespec ts;
-	clock_gettime(CLOCK_UPTIME,&ts);
-	return (((u_int64_t) ts.tv_sec) * NANOSEC + ts.tv_nsec);
-}
-#endif
-#endif /* _SOLARIS_C_SOURCE */
-
 #endif /* !_SYS_TIME_H_ */
diff --git a/sys/sys/types.h b/sys/sys/types.h
index 6273f7cbfc00..51c02c8b553c 100644
--- a/sys/sys/types.h
+++ b/sys/sys/types.h
@@ -296,36 +296,6 @@ typedef	struct vm_page	*vm_page_t;
 
 #endif /* !_KERNEL */
 
-/*
- * Solaris compatibility definitions.
- */
-#ifdef _SOLARIS_C_SOURCE
-typedef u_int		uint_t;
-typedef u_char		uchar_t;
-typedef u_short		ushort_t;
-typedef u_long		ulong_t;
-
-typedef	long long	longlong_t;  
-typedef unsigned long long	u_longlong_t;
-
-typedef off_t		off64_t;
-
-typedef id_t		taskid_t;
-typedef id_t		projid_t;
-typedef id_t		poolid_t;
-typedef id_t		zoneid_t;
-typedef id_t		ctid_t;
-
-#ifndef _KERNEL
-#if defined(__XOPEN_OR_POSIX)
-typedef enum { _B_FALSE, _B_TRUE } boolean_t;
-#else
-typedef enum { B_FALSE, B_TRUE } boolean_t;
-#endif /* defined(__XOPEN_OR_POSIX) */
-#endif
-
-#endif /* _SOLARIS_C_SOURCE */
-
 /*
  * The following are all things that really shouldn't exist in this header,
  * since its purpose is to provide typedefs, not miscellaneous doodads.