Para rubber (Hevea brasiliensis) seeds were examined for their proximate analysis, detergent fibre, amino acid and mineral composition. The seeds were further analysed for the prescence of antitrypsin activity, cyanide, phytate and tannins. The average composition of the seed kernel was, on a DM basis, 21.5;crude protein, 50.2;crude fat, 6.5;crude fibre, 3.6;ash and 18.2;carbohydrates. The amino acid profile, when compared with the NAS/NRC reference protein pattern, revealed deficiencies of lysine, isoleucine and theronine. The seed kernels contained reasonable amounts of trace minerals, but were poor sources of calaium and phosphorous. Fresh seed kernel samples contained toxic concentrations of cyanide (164 mg/100 g dry weight), but most of the cyanide was elliminated by storage and cooking. The relatively high content of phytate P (37.5;of total P) may be expected to aggravate further the problem of low P and to cause severe Ca and P imbalance. No antitryptic activity or tannis was detected. Because of the prescence of an antifertility factor and collection and storage problems, it is concluded that rubber seeds show little promise as a human food in normal times.