The toxicity of heavy metals (Zn, Pb) and diesel, in single and binary solution was investigated using the photobacterium Vibrio fischeri (Microtox test) as a test organism. In this experiment, the concentration of water soluble fraction of diesel was based on the total petroleum hydrocarbon (TPH). The toxicity of each single compound showed the following $EC_{50}$ (15min): Zn 1.90 mg/L, Pb 0.31 mg/L, TPH 2.09 mg/L. The observed toxicity of binary mixtures increased, depending on the concentration of the mixed substance. The effects were defined as synergistic, antagonistic, or additive, in accordance with the sign of difference between the predicted and observed toxicity at binary mixtures. The interactive effects between zinc and lead were synergistic, on the other hand, antagonistic and additive effects were found in each metal and TPH mixtures on the bioluminescence of V. fischeri.