Abstract Combined effects on rabbits induced by γ-rays irradiation in combination with inhalation of benzene, toluene and carbon monoxide and the interactive characteristics （antagonistic, additive or synergistic） of these agents were studied. Ninety healthy male rabbits were equally divided into 9 groups, eight of which were test groups assigned according to four-factor- two-dose-level orthogonal layout [L,8,（2,7,）] program and one was the control. The two dose-levels of the four factors were: for γ-rays irradiation, 0.0075Gy/d and 0.0375Gy/d, and for benzene, toluene and carbon monoxide, 40±15mg/m,3, and 182±33mg/m,3, 90±30mg/m,3, and 407±68mg/m,3, 93±4mg/m,3, and 278±8mg/m,3, respectively. The animals were exposed to γ-rays irradiation combined with benzene, toluene and CO vapor 2h a day and 5days a week for a period of 8 weeks. Experimental results were analysed with the method of variance analysis and the test groups were compared. The results showed that （1） the interactive factor, the ratio,（ω）, of the combined effects caused by the four agents to the sum of the four independent effects induced by those agents, was 2.16, 1.58, 2.07, 2.67, 1.31 and 1.18 for dicentric + ring, acentric, aberration cells, total aberration, micronuclei and SCEs/C in lymphocytes respectively, and the ratio for aberrant sperms was as high as 5.97. The ratios showed that interactions were mainly synergistic （ω,>,1）. However, for acentric interactions between γ-rays and benzene was antagonistic. （2） The four agents could all obviously cause decrease in testis weight index, and γ-rays, benzene and CO could markedly reduce the number of sperms and increase the ratio of aberrant sperms. The interactions between γ-rays and benzene for the decrease in testis weight index and for the elevation of the ratio of aberrant sperms were synergistic. （3） CO could cause decrease in total amount of leucocytes, thrombocytes and hemoglobin, and toluene cause decrease in lymphocytes. （4） Gamma rays irradiation combined with inhalation of benzene, toluene and CO could produce significant interactions which were mainly synergistic, and CO, when combined with γ-rays, benzene and toluene, could cause obvious effects on gland.