diff --git a/wmail/configure.in b/wmail/configure.in
index 84d2ded..7054c52 100644
--- a/wmail/configure.in
+++ b/wmail/configure.in
@@ -39,6 +39,7 @@ AC_SUBST(X_LIBRARY_PATH)
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
+AC_TYPE_SIZE_T
 
 dnl Checks for library functions.
 AC_FUNC_FNMATCH
diff --git a/wmail/src/common.c b/wmail/src/common.c
index f479389..c3bb506 100644
--- a/wmail/src/common.c
+++ b/wmail/src/common.c
@@ -78,8 +78,8 @@ void WARNING( const char *fmt, ... )
 char *MakePathName( const char *dir, const char *file )
 {
     char *fullName;
-    int len1 = strlen( dir );
-    int len2 = strlen( file );
+    size_t len1 = strlen( dir );
+    size_t len2 = strlen( file );
 
     if( dir[len1-1] != '/' )
 	fullName = malloc( len1 + len2 + 2 );
diff --git a/wmail/src/config.c b/wmail/src/config.c
index 7671f15..b58b847 100644
--- a/wmail/src/config.c
+++ b/wmail/src/config.c
@@ -126,7 +126,7 @@ static enumList_t tickerEnum[] =
 
 static bool Tokenize( const char *line, const char **id, const char **value )
 {
-    int len;
+    size_t len;
     const char *token1, *token2;
 
     if( line != NULL )
@@ -270,7 +270,7 @@ void ReadConfigFile( bool resetConfigStrings )
 		for( ; !feof( f ); ++line )
 		{
 		    const char *id, *value;
-		    unsigned int len;
+		    size_t len;
 
 		    if( fgets( buf, 1024, f ) == NULL )
 			break;
diff --git a/wmail/src/wmail.c b/wmail/src/wmail.c
index 3c3fca4..157c389 100644
--- a/wmail/src/wmail.c
+++ b/wmail/src/wmail.c
@@ -529,7 +529,7 @@ static void WriteChecksumFile( bool writeAll )
 static void UpdateChecksum( unsigned long *checksum, const char *buf )
 {
     if( buf != NULL ) {
-	unsigned int i, len = strlen( buf );
+	size_t i, len = strlen( buf );
 
 	for( i = 0; i < len; ++i )
 	    *checksum += buf[i] << (( i % sizeof(long) ) * 8 );
@@ -919,7 +919,7 @@ static char *ParseFromField( char *buf )
     char *addressName;
     char *atChar = NULL;
     char *c;
-    int maxLen = strlen( buf ) + 1;
+    size_t maxLen = strlen( buf ) + 1;
     char *comment;
 
     if(( fullName = calloc( maxLen, sizeof *fullName )) == NULL )
@@ -1088,7 +1088,7 @@ static char *ParseFromField( char *buf )
 static bool SkipSender( char *address )
 {
     char **skipName;
-    int len = strlen( address );
+    size_t len = strlen( address );
 
     // remove trailing '\n' got from fgets
     if( address[len-1] == '\n' )