A simple and sensitive spectrophotometric method has been developed for the determination of clarithromycin in pure and commercial pharmaceutical formulations. The method involves formation of colored ion-associate complex of clarithromycin with bromothymol blue in acidic media (acetate buffer solution). The colored complex was extracted in chloroform which showed the optimum wavelength at 420 nm. Various conditions such as wavelength, acetate buffer pH, acetate buffer volume, bromothymol blue solution concentration and bromothymol blue solution volume were investigated. At the optimum conditions, the method has been applied for the determination of clarithromycin in commercial pharmaceutical formulations. The investigated spectrophotometric method has numerous advantages, for examples, the use of inexpensive chemicals, sensitivity and reproducibility and can be used as alternatives for routine analysis of clarithromycin.