I'm sure I'm doing something stupid here, but I think I've got the syntax right ? The error I'm seeing: psql:event_session_funcs.sql:26: ERROR: syntax error at or near "[" LINE 11: VALUES(p_event_id,[p_start_time,p_end_time)) RETURNI... The function: CREATE OR REPLACE FUNCTION new_event_session(p_event_id text, p_start_time timestamptz, p_end_time timestamptz, p_sess_title text, p_sess_desc text ) RETURNS text AS $$ DECLARE v_session_id text; BEGIN INSERT INTO event_sessions(event_id,evt_sess_times) VALUES(p_event_id,[p_start_time,p_end_time)) RETURNING evt_sess_id INTO v_session_id; // REST OF FUNCTION REMOVED FOR BREVITY The table definition: CREATE TABLE IF NOT EXISTS event_sessions ( event_id text NOT NULL, evt_sess_id text NOT NULL PRIMARY KEY DEFAULT ksuid_pgcrypto_micros(), evt_sess_times tstzrange NOT NULL, evt_sess_inserted timestamptz not null default now(), CONSTRAINT fk_evt_id FOREIGN KEY(event_id) REFERENCES events(event_id), EXCLUDE USING gist ( event_id WITH =, evt_sess_times WITH && ) ); N.B. I'm calling from Go, the library does not natively support tstzrange, hence the need to break-out the input parameters. Thanks !