One of the most chemical methods for controlling of oil spills is use of dispersants, which are widely being used worldwide. In this research, comparison of acute toxicity of crude oil of the Persian Gulf-Khark area (CO), Iranian Naftroob crude oil dispersant (IND), Radiagreen OSD dispersant crude oil (RD), the mixture of crude oil and Iranian Naftroob dispersant (CO-IND) and crude oil with Radiagreen OSD dispersant (CO-RD) was carried out. For this purpose, the concentrations of both dispersants were equal: 10.5, 21, 42, 84 and 168 mg/L. The concentrations of 8.4+16, 16.8+336, 33.6+672, 67.2+1344 and 134.4+2688 mg/L were used for dispersants-crude oil mixtures and the concentrations of 168, 336, 672, 1344 and 2688 mg/L were used for crude oil alone. litopenaeus vannamei was used for bioassay toxicity test.48-h LC50 was estimated by Probit value table. Relationship between efficiency and toxicity (RET) was also estimated.48-h LC50 for CO, IND, RD, CO-IND and CO-RD were 1741, 17.21, 43.52, 631.456, 357.089 mg/L, respectively. The results were obtained by these tests were shown that CO alone is less toxic than the IND, RD and also COIND and CO-RD. Moreover, CO-IND was less toxic than CO-RD. With regard to the efficiency of IND had a lower (RET=34.8) than RD (RET=39) and so, it was more efficient.