diff --git a/configure.ac b/configure.ac
index dc8c3b4..e4d3c2c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4,7 +4,7 @@
 AC_PREREQ([2.67])
 AC_INIT()
 AC_CONFIG_AUX_DIR([config])
-AC_CONFIG_SRCDIR([src/IOR.c])
+AC_CONFIG_SRCDIR([src/ior.c])
 AC_CONFIG_HEADERS([config.h])
 
 AC_CANONICAL_HOST
diff --git a/src/Makefile.am b/src/Makefile.am
index 789359e..28b9cb9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2,8 +2,8 @@ SUBDIRS = cbif
 
 bin_PROGRAMS = ior
 
-ior_SOURCES = IOR.c utilities.c parse_options.c
-ior_SOURCES += IOR.h aiori.h iordef.h defaults.h
+ior_SOURCES = ior.c utilities.c parse_options.c
+ior_SOURCES += ior.h aiori.h iordef.h defaults.h
 ior_LDADD = -lm
 
 if USE_POSIX_AIORI
diff --git a/src/aiori-NCMPI.c b/src/aiori-NCMPI.c
index 114a821..39fb533 100644
--- a/src/aiori-NCMPI.c
+++ b/src/aiori-NCMPI.c
@@ -195,7 +195,7 @@ IOR_Xfer_NCMPI(int            access,
     int            segmentNum,
                    transferNum;
 
-    /* Wei-keng Liao: In IOR.c line 1979 says "block size must be a multiple
+    /* Wei-keng Liao: In ior.c line 1979 says "block size must be a multiple
        of transfer size."  Hence, length should always == param->transferSize
        below.  I leave it here to double check.
     */
diff --git a/src/aiori.h b/src/aiori.h
index e81d2d4..6d5b9ae 100644
--- a/src/aiori.h
+++ b/src/aiori.h
@@ -53,8 +53,8 @@
  *
  * NOTE: If this is changed, also change:
  *         defaultParameters [defaults.h]
- *         DisplayUsage() [IOR.c]
- *         ShowTest() [IOR.c]
+ *         DisplayUsage() [ior.c]
+ *         ShowTest() [ior.c]
  *         DecodeDirective() [parse_options.c]
  *         ParseCommandLine() [parse_options.c]
  *         USER_GUIDE
diff --git a/src/IOR.c b/src/ior.c
similarity index 99%
rename from src/IOR.c
rename to src/ior.c
index 77bf02e..a8a42e6 100644
--- a/src/IOR.c
+++ b/src/ior.c
@@ -6,7 +6,7 @@
 \******************************************************************************/
 
 #include "aiori.h"                                    /* IOR I/O interfaces */
-#include "IOR.h"                                      /* IOR definitions
+#include "ior.h"                                      /* IOR definitions
                                                          and prototypes */
 #include <ctype.h>                                    /* tolower() */
 #include <errno.h>                                    /* sys_errlist */
diff --git a/src/IOR.h b/src/ior.h
similarity index 99%
rename from src/IOR.h
rename to src/ior.h
index 59f7cd0..79553fa 100644
--- a/src/IOR.h
+++ b/src/ior.h
@@ -26,7 +26,7 @@ typedef struct IOR_queue_t {
 
 /**************************** P R O T O T Y P E S *****************************/
 
-/* functions used in IOR.c */
+/* functions used in ior.c */
 void           AioriBind        (char *);
 void           CheckForOutliers (IOR_param_t *, double **, int, int);
 void           CheckFileSize    (IOR_param_t *, IOR_offset_t, int);
diff --git a/src/parse_options.c b/src/parse_options.c
index 035099e..d63908c 100644
--- a/src/parse_options.c
+++ b/src/parse_options.c
@@ -9,7 +9,7 @@
 *
 \******************************************************************************/
 
-#include "IOR.h"
+#include "ior.h"
 #include "defaults.h"                                 /* IOR defaults */
 
 #include <ctype.h>
diff --git a/src/utilities.c b/src/utilities.c
index e572e23..85a3f4c 100644
--- a/src/utilities.c
+++ b/src/utilities.c
@@ -10,7 +10,7 @@
 \******************************************************************************/
 
 #include "aiori.h"                                  /* abstract IOR interface */
-#include "IOR.h"                                    /* IOR functions */
+#include "ior.h"                                    /* IOR functions */
 #include <errno.h>                                  /* sys_errlist */
 #include <fcntl.h>                                  /* open() */
 #include <math.h>                                   /* pow() */