Yield responses of some economically important crop plants due to foliar applications of low concentrations of 28-homobrassinolide (HBR) were studied in experiments conducted at research stations and in farmers' fields in India during 1989–95. Foliar sprays of different concentrations of HBR were applied at tillering and spike/panicle initiation in wheat (0·5 and 1·0 mg/l) and rice (0·25, 0·50 and 1·00 mg/l); at flowering and pegging in groundnut (0·25 and 0·50 mg/l); 30 and 45 days after sowing (DAS) in mustard (0·25 and 0·50 mg/l); 25 and 35 days after emergence in potato (0·25 and 0·50 mg/l); and 30, 50, 70 DAS in cotton (0·1 and 1·0 mg/l). The HBR treatments significantly (P<0·05 and P<0·01) increased grain yields in wheat, rice and mustard, pod yields in groundnut, tuber yields in potato and seed cotton yields, over control. The extent of yield improvement due to HBR was influenced by crop species, concentration of HBR, plant growth stage at application and frequency of application.