A field experiment was conducted during the rabi seasons of 2010 to 2013 to find out the optimum time of sowing and plant spacing for broccoli (var. KTS-1) seed production. Seedlings raised by sowing on four different dates viz. 10th October, 30th October, 20th November and 10th December were transplanted at two spacing viz. 45 cm x 45 cm and 60 cm x 45 cm. Yield and yield attributing characters were significantly influenced by the treatments. Sowing on 10th October produced the highest head yield (137.81q/ha) while 10 December sowing produced the lowest head yield (6.75 q/ha) of broccoli. Closer spacing (45 cm x 45 cm) gave significantly higher head yield (88.28 q/ha) than planting at 60 cm x 45 cm distance. The highest seed yield (177 kg/ha) was obtained on planting 10 October sown seedlings at 45 cm x 45 cm distance and was the most remunerative (B: C ratio of 6.44) among all the treatment combinations. Plants from delayed sowing of 20th November and 10th December failed to produce viable seeds under agro-climatic condition of Assam.