The trial of Rodney D. Clinton, who is accused of fatally stabbing his mother last Feb. 16, was postponed for a fifth time yesterday because his lawyer was ill.

The trial in Baltimore Circuit Court was postponed four other times because Mr. Clinton, 35, was undergoing psychiatric evaluation. He is using the insanity defense.

The psychiatric evaluations still are not complete.

The trial has been rescheduled for March 23.

Police said that on Feb. 16, Mr. Clinton visited his mother, Annie Clinton, 61, at her home in the 800 block of Allendale St., and stabbed her during an argument.