Tlco, Kco (Tlco/Va), Va, Vc and Dm were measured in 25 flour mill workers (non-smoker 9, smoker 16) and 50 healthy control subjects (25 non-smoker, 25 smoker) of similar anthropometric parameters and socio-economic status. Tlco (P < 0.05) was decreased significantly and rest of the parameters were decreased insignificantly in flour mill workers as compared to control subjects. In non-smoker flour mill workers none of the parameters altered significantly as compared to non-smoker control subjects. Statistically significant reduction was seen in smoker workers only in Tlco (P < 0.05) and its component Dm (P < 0.05) as compared to smoker control subjects. Further it has been observed that less duration of flour dust exposure (< 5 years) in all flour mill workers and smoker flour mill workers caused negligible fall in Tlco, whereas longer duration of flour dust exposure (> 5 years) in both the groups caused highly significant fall in Tlco (P < 0.01) which was contributed to by highly significant fall in Dm (P < 0.001).