diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
index c8e6961da..7544ef25f 100644
--- a/man7/system_data_types.7
+++ b/man7/system_data_types.7
@@ -104,6 +104,25 @@ POSIX.1-2001 and later.
 .IR "See also" :
 .BR stat (2)
 .RE
+.\"------------------------------------- blksize_t --------------------/
+.TP
+.I blksize_t
+.RS
+.IR Include :
+.IR <sys/types.h> .
+Alternatively,
+.IR <sys/stat.h> .
+.PP
+Used for file block sizes.
+According to POSIX,
+it shall be a signed integer type.
+.PP
+.IR "Conforming to" :
+POSIX.1-2001 and later.
+.PP
+.IR "See also" :
+.BR stat (2)
+.RE
 .\"------------------------------------- cc_t -------------------------/
 .TP
 .I cc_t