A new and selective spectrophotometric method for the determination of trace amounts of Pb(II) in aqueous environmental samples is reported. The interaction in solution between Pb(II) and Benzoic acid Azo Phenyl Calix[4]arene (BAPC) was studied. Upon reaction of PABC and Pb(II) a stable complex is formed. Under the conditions reported here the method furnishes reproducible results with basic media. The calixarene derivative shows strong binding ability to Pb²⁺ ion with formation of a 1:1 complex. Beer's law is obeyed in the range of 2.0´10^-6 - 2.4´10^-5 molL^-1 of Pb²⁺. The apparent molar absorptivity (e) of 1-Pb²⁺ complex was 1.89 x10⁴ Lmol^-1cm^-1 at 440 nm, and the detection limit is 1.4x10^-6 mol L^-1. The BAPC showed high sensitivity and selectivity for Pb²⁺. The method was used to determine the content of Pb(II) in synthetic and natural samples.