The present study was aimed for the effects of exposure to multiple organic solvent vapors in comparison with single exposure to phenol. It included 20 workers exposed to phenol alone and 32 workers of combined exposure to phenol, benzene, toluene and methyl ethyl ketone. A control group of 30 subjects was also included. The levels of transaminases, total proteins, prothrombin time, bleeding time, clotting time, fasting blood sugar, serum creatinine and some trace elements (copper, zinc, iron, magnesium, manganese and calcium) were determined in blood together with a complete blood picture. Urine samples were analyzed for phenol, hippuric acid and methyl ethyl ketone. The effects of combined exposure did not differ from that of exposure to phenol alone concerning the majority of the tested parameters. Only the levels of platelets count, prothrombin time, eosinophils, copper and iron have been affected by combined exposure in a probably additive manner.