The challenges are explained in this brief, which limit the use of improved rice seed in three major rice growing districts in Eastern Uganda. Insufficient supply of improved seed is a core constraint to intensification in rice production. In the three study districts, there are only four rice seed producers, which renders rice seed to be the hardest input to access by farmers compared to fertilizer, herbicides, and fungicides. The inaccessibility of rice seed is further compounded by producers having contractual obligations with external seed companies. The volume of seed required by farmers exceeds the supply capabilities of the four seed producers, creating a gap in the rice seed supply chain. Furthermore, the seed producers rarely multiply the varieties grown by farmers, but rather those demanded by seed companies outside the region. The estimated seed supply gap is about 90 percent of what farmers would require. Therefore, in order to meet local farmer’s requirement for improved rice seed, at least 40 new seed production enterprises should be established and this is estimated to cost slightly over one billion Uganda shillings (US $ 300,000).