This invention relates to flame retardants for polyester and polyamide compositions, and specifically relates to compositions containing (1) about 30 to about 70 weight percent of a polyester or a synthetic, aliphatic polyamide; (2) about 15 to about 40 weight percent of glass or mineral reinforcing agent; and (3) a flame retardant of (a) about 20 to about 30 weight percent of melamine phosphate and up to about 10 weight percent of a charring catalyst; (b) about 15 to about 30 weight percent of melamine phosphate, up to about 10 weight percent of a charring catalyst and up to about 10 weight percent of a char former; (c) about 25 to about 30 weight percent of melamine pyrophosphate; (d) about 15 to about 30 weight percent of melamine pyrophosphate and up to about 10 weight percent of a charring catalyst; or (e) about 15 to about 30 weight percent of melamine pyrophosphate, up to about 10 weight percent of a charring catalyst and up to about 10 weight percent of a char former, wherein all percents by weight are based on the total weight of (1)+(2)+(3) only.