A simple, sensitive and selective spectrophotometric method has been developed for determination of p-benzoquinone, tetrachloro-p-benzo-quinone, 1,4-napthaquinone and menadione (vitamin K3). The method is based on reaction of these quinones with excess piperidine in ethylalcohol. The colored products obtained display a maximum absorption at δ = 370-510 nm, depending upon the type of quinone used, E1%1 cmin the range 72-870. The effects of time, temperature and concentration on the nature of the reaction products have been investigated. The results obtained with an average recovery of 93.75%.