The charge transfer reaction between clotrimazolum and alizarin red was studied spectrophotometrically. The reaction was achieved with good results in water-acetone solution. The apparent molar absorptivity is 8.7 x 10(3) L.mol-1.cm-1 at 525 nm. The Beer's law was obeyed in the range of 0-100 micrograms.mL-1 of clotrimazolum. The composition of the complex is 1:1. The proposed method has been applied successfully to the determination of clotrimazolum tablets.