A method based on Rimini test for aliphatic amines was studied and developed for quantitative estimation of aliphatic primary amines. The method involves action of the amine with acetone to form schiff base which complexes with sodium nitroprusside to give violet colour. The absorption maximum in the visible range of the spectrum, for the reaction mixture was found to be 550 nm. The pH (8-11) and reaction time scan for the assay were optimized. A linear relation of concentration (0.2-3 mg/mL) of amine against absorbance at 550 nm was established. Interference due to other reaction components was negligible (+/- 0.02 mg/mL) as compared to the sample in buffer. 1,3-dimethyl butylamine was used as the model amine and the method was applied to other amines; it was observed that when electron-withdrawing substituents are present in the molecule the reaction is retarded, as the incubation time was longer. This method is useful for estimation of aliphatic primary amine in biological samples.