A selective and sensitive spectrophotometric and atomic absorption spectrophotometric method is developed for the determination of traces of mercury with N-phenylcinnamohydroxamic acid (PCHA) in the environment. Mercury is extracted into a chloroform solution of PCHA at pH 8.5-10.0 and determined by AAS. The mercury hydroxamate binary complex is yellow in colour having a maximum absorbance at 390 nm and molar absorptivity 4.3 × 1031 mol−1cm−1, sandell sensitivity 0.0466 μg/cm2. The ternary system using 1-(2-pyridylazo)-2-naphthol has molar absorptivity 8.82 × 1031 mol−1cm−1at 550nm, sandell sensitivity 0.0228 μ/cm2. Beer's law is obeyed in the concentration range of 2.37-38.0 ppm and 0.80-19.5 ppm of mercury for binary and ternary system, respectively. The extraction of Hg-PCHA binary system is studied with a liquid cation exchanger, bis-(2-ethyl hexyl) phosphoric acid (HDEHP) and found to have better selectivity than Hg-PCHA-PAN system. The molar absorptivity of the Hg-PCHA-HDEHP system is 8.82 × 1031 mol−1cm−1at 390 nm and Beer's law is obeyed in the concentration range of 0.47-20 ppm of mercury.