Abstract: The effects of chronic exposure to crude acetylene on some biochemical and haematological indices were studied in New Zealand White rabbits exposed to inhalation of 58,000 ppm crude acetylene for 10 min at 12 h intervals for 3 weeks. The treatment provoked significant elevation of aspartate and alanine transaminases in plasma of test rabbits relative to controls (p<0.001; p<0.005). In addition, catalase activity was significantly depressed in the heart, liver and kidney tissues (p<0.005), while superoxide dismutase was significantly raised in heart tissue (p<0.008). Packed cell volume was significantly lower in rabbits exposed to crude acetylene (p<0.05), while marginal decreases were seen in the other haematological parameters investigated. These results suggest that unlike pure industrial acetylene, crude acetylene may have deleterious effects on vital organs and blood constituents. Thus the use of in situ generated acetylene by welders may be hazardous to health.