The cyanide content of rubber seeds was estimatd by autolysis techniques. Autolysis of random seed samples yielded total cyanide contents ranging from 100 to 4000 mg/kg. Six samples collected from the same field, one day after seed fall (in an attempt to limit the variation), yielded an average cyanide content of 1819 mg/kg. Comparison of seeds from the same fruit found wide variations in cyanide content, e.g. 15-1897 mg/kg in one fruit, indicating a need for large seed samples. An optimum sample size of 6-8 g is suggested. Hydrolysis with trichloroacetic acid [TCA] for 4 h yielded <3;of the total cyanide. Using 2M H2SO4 at room temperature also yielded very little. Acid reflux for 30 h yielded the full amount, but autolysis took only 2 h to do the same. Adding exogenous linamarase to distilled autolysate residue did not release any further cyanide.