Quantitative determination of the activity of acid phosphatase detected in tissue sections using Burstone's method. The experiment was performed on inbred rats. A reaction for AcP according to Burstone was made in liver sections, incubation time was fixed experimentally. The material obtained from each animal was divided into 3 parts. One of them was used for enzymatic estimations, the 2nd for planimetry of sections, and the 3rd was eluted by N,N-dimethylformanid, and the obtained coloured product was subjected to spectrophotometric analysis at the Spectrophotometer Unicam SP 8000 B. Homogeneity of the coloured product eluted from the sections as well as its identity with the coloured product obtained during the reaction with a preparation of crystalline acid phosphatase was found. Repeatability of the obtained activity for the inbred animals was shown. The obtained results were subjected to statistical analysis. The method of quantitative estimation of AcP activity may be useful in histoenzymatic works.