The separation of Hg(II) and As(V) from produced water by hollow fiber contactors was investigated. Two identical hollow fiber modules were employed. The first module was used for extraction, while the second module was used for stripping. The optimum conditions achieved were 14% (v/v) of Aliquat336, 0.07 M thiourea, volumetric flow rate of 100 mL/min for aqueous solution and 0.02 M HCl of stripping solution. At such conditions, the maximum extraction of Hg(II) and As(V) attained 100% and 78.78%, respectively. Concurrently, the maximum stripping of Hg(II) and As(V) reached 47.88% and 6.66%, respectively. The overall mass transfer coefficients of Hg(II) and As(V) extraction were 2.31×10−6 and 1.15×10−6m/s, while the Hg(II) and As(V) stripping exhibited the overall mass transfer coefficients of 8.37×10−7 m/s and 9.05×10−7 m/s, respectively. Mass transfer coefficients of the organic layer diffusion (k0) had the most effect on the overall mass transfer coefficients.