The sexual maturity of female Siamese gourami, Trichogaster pectoralis was studied by determining fecundity and gonadosomatic index (GSI). It was found that the size at sexual maturity of female Siamese gourami was 18.07±1.10 cm (mean±SD) in average total length and 94.20±13.39 g in average body weight. The fecundity was 26,261±5,215.81 ova/fish and gonadosomatic index (GSI) was 10.9±2.1%. Newly hatched larvae of Siamese gourami were produced by induced spawning using chemical in- jection (Suprefact and Motilium). The sexually mature fishes were cultured in fiber-glass tank (water volume 300 liters) with the ratio of male and female brooders 1:1. The fertilization rate, hatching out and hatching rate experiments were carried out using a 15-liter aquarium (water volume 10 liters) containing 1,000 eggs. It was found that the eggs were floating and rounded. The fertilized eggs had a diameter of 908.25±39.13 µµ µµ µm. The average fertilization rate was 91.12%, hatching out was 22 hr 10 min and average hatching rate was 83.03% at a water temperature of 27.0-30.5ºC. Sampling of the newly-hatched larvae was done at 2-hour