Four-wave mixing in a 6 -m long single-mode tellurite (78TeO2-5Bi2O3-5ZnO-12Na2O, mol%, TBZN) fiber was experimentally observed with the continuous-wave (CW) pump wavelengths changing from ∼1530 to 1565 nm. Conversion efficiency of ∼−20 dB was obtained with the CW signal input power of ∼5 mW at the pump wavelength of ∼1565 nm. The optical signal gain in the TBZN tellurite fiber was numerically simulated, and the result agreed well with the experiment.