Abstract: An experiment was conducted in the Rabi seasons of 1999 and 2000 to investigate the appropriate plant population of onion as a companion crop that would not adversely affect the chilli yield and also to assess the economic benefit. The results showed that the yields of chilli decreased with the increase of onion population but the chilli yields when intercropped with 20-80% onion population were not significantly decreased. The highest average yields of dry chilli (1546 kg ha‾1) and onion (8042 kg ha‾1) were observed from their respective sole crops. Average over two years data, all intercropping treatments gave higher chilli equivalent yield and net monetary return per hectare than the sole chilli. In addition, the highest average chilli equivalent yield (2732 kg ha‾1), land equivalent ratio (1.34) and net return (Tk. 46,395.00 ha‾1) were obtained from 20% onion population intercropped with chilli indicating the practice of intercropping of chilli at different onion population was more profitable than the conventional monoculture of chilli.