diff --git a/src/dblib.cppo.ml b/src/dblib.cppo.ml
index eb9b98a..d96a280 100644
--- a/src/dblib.cppo.ml
+++ b/src/dblib.cppo.ml
@@ -151,6 +151,7 @@ type col_type =
   | SYBMONEY4 (* 17 *) | SYBMONEY (* 18 *) | SYBMONEYN (* 19 *)
   | SYBREAL (* 20 *)
   | SYBBINARY (* 21 *) | SYBVARBINARY (* 22 *)
+  | SYBUNIQUE (* 23 *)
 
 let string_of_col_type = function
   | SYBCHAR -> "CHAR"
@@ -168,6 +169,7 @@ let string_of_col_type = function
   | SYBBINARY -> "BINARY" | SYBVARBINARY -> "VARBINARY"
   | SYBNUMERIC -> "NUMERIC"
   | SYBDECIMAL -> "DECIMAL"
+  | SYBUNIQUE -> "UNIQUEIDENTIFIER"
 ;;
 external coltype : dbprocess -> int -> col_type = "ocaml_freetds_dbcoltype"
 
diff --git a/src/dblib.mli b/src/dblib.mli
index 7287e9a..8786a1a 100644
--- a/src/dblib.mli
+++ b/src/dblib.mli
@@ -145,6 +145,7 @@ type col_type =
   | SYBMONEY4 | SYBMONEY | SYBMONEYN
   | SYBREAL
   | SYBBINARY | SYBVARBINARY
+  | SYBUNIQUE
 
 val string_of_col_type : col_type -> string
 (** Returns a string description of the column type. *)
diff --git a/src/dblib_stubs.c b/src/dblib_stubs.c
index 1eb2a4b..52d6160 100644
--- a/src/dblib_stubs.c
+++ b/src/dblib_stubs.c
@@ -552,6 +552,7 @@ CAMLexport value ocaml_freetds_dbcoltype(value vdbproc, value vc)
   case SYBREAL: CAMLreturn(Val_int(20));
   case SYBBINARY: CAMLreturn(Val_int(21));
   case SYBVARBINARY: CAMLreturn(Val_int(22));
+  case 36 /* SYBUNIQUE */: CAMLreturn(Val_int(23));
   }
   if (ty == -1)
     /* The handler catches this exception.  Raise a compatible one. */
@@ -713,6 +714,13 @@ CAMLexport value ocaml_freetds_get_data(value vdbproc, value vcol,
     COPY_STRING(vres, data, len);
     CONSTRUCTOR(0, vres);
     break;
+  // SYBUNIQUE is not consistently exported in FreeTDS headers due to "an oversight"
+  case 36 /* SYBUNIQUE */:
+    // Unique identifier should be 16 bytes
+    // When converting to a string, the result is 36 characters (32 hex characters + 4 dashes)
+    CONVERT_STRING(36);
+    CONSTRUCTOR(0, vres);
+    break;
   case SYBIMAGE:
   case SYBBINARY:
   case SYBVARBINARY:
diff --git a/test/test_dblib.ml b/test/test_dblib.ml
index 2842855..cf80980 100644
--- a/test/test_dblib.ml
+++ b/test/test_dblib.ml
@@ -106,13 +106,28 @@ let test_data params _ =
                           CAST('a' AS CHAR(10)) AS c, \
                           CAST('abc' AS TEXT) AS txt, \
                           CAST(1 AS INT) AS i, \
-                          CAST(3.4 AS DOUBLE PRECISION) AS d";
+                          CAST(3.4 AS DOUBLE PRECISION) AS d, \
+                          CAST('b6702d1b-8082-4475-90c9-07e51aef9e7c' AS UNIQUEIDENTIFIER) AS u";
       Dblib.results conn
       |> assert_bool "query has results";
+      Dblib.numcols conn
+      |> assert_equal ~printer:string_of_int 6;
+      Dblib.coltype conn 1
+      |> assert_equal ~printer:Dblib.string_of_col_type SYBCHAR;
+      Dblib.coltype conn 2
+      |> assert_equal ~printer:Dblib.string_of_col_type SYBCHAR;
+      Dblib.coltype conn 3
+      |> assert_equal ~printer:Dblib.string_of_col_type SYBTEXT;
+      Dblib.coltype conn 4
+      |> assert_equal ~printer:Dblib.string_of_col_type SYBINT4;
+      Dblib.coltype conn 5
+      |> assert_equal ~printer:Dblib.string_of_col_type SYBFLT8;
+      Dblib.coltype conn 6
+      |> assert_equal ~printer:Dblib.string_of_col_type SYBUNIQUE;
       Dblib.nextrow conn
       |> assert_equal ~printer:string_of_row
            Dblib.([STRING "a"; STRING "a         "; STRING "abc";
-                   INT 1; FLOAT 3.4])
+                   INT 1; FLOAT 3.4 ; STRING "B6702D1B-8082-4475-90C9-07E51AEF9E7C"])
     )
 
 let test_insert params _ =