The infrared spectra of organic and inorganic constituents of urine from cancerous bladders ofsome patients were recorded. The spectra of the organic part of the samples were classified into fivetypes according to the bulk constituents. Samples with type A spectra consisted mainly of proteinswith only trace amounts of lipids. Their spectra were characterized mainly by the absorption bandsof proteins at the frequencies 3330, 3075, 2960, 2850, 1650, 1530, 1450, 1400 and 1320 cm-1 inaddition to a weak band at 1720 cm-1 due to the absorption of lipids. Samples with type B spectrawere characterized by high amounts of proteins and low amounts of lipids and phosphate com- pounds. The presence of phosphate compounds was indicated by the absorption bands at the fre- quencies 1100 and 1030 cm-1. Samples giving spectral type C were characterized by high ureacontents as indicated by the presence of two strong bands at 1670 and 1630 cm-I-. Samples with thespectral type D consisted of urea and phosphate compounds whereas samples with the last spectraltype E consisted mainly of calcium oxalates, uric acids and phosphate compounds. The presence ofcalcium oxalates was indicated by the presence of its diagnostic bands at the frequencies 1630and 1330 cm-1 while the presence of uric acid was indicated by the bands at the frequencies 1360,1130, 1020 and 880 cm-1. On the other hand, the spectra of the organic part of urine from somenormal bladders exhibited the characteristic bands of urea only.