The study draws upon data collected in 1994 from 200 farm household in 10 thanas, purposively selected to represent major geographic and agro-ecological zones in the Bangladesh. The paper attempts to identify problems associated with diversified crops, based on farmers' perceptions. More importantly, farm characteristics are examined to explain levels of crop diversity or specialization; and results from regression analyses are presented. In the latter exercise, Simpson Index of diversity as well as Rice-share Index have been used. The survey results suggest several constraints to crop diversity, such as, low profitability, high input cost, risk in selling non-rice crops, susceptibility to weather variation and pests. The Simpson Index of diversity is found to decline with farm size, implying that large farmers specialize in few crops, particularly rice and few cash crops. Among other things, proximity to towns increase crop diversity while credit is found to reduce it. The study was however unable to identify any relationship between efforts by NGOs and the degree of crop diversity on farms.