In this research, an investigation on carbone monoxide in heavy traffic intersections of Kerman municipal districts in 2003-2004 has been performed. Kerman City is located at the south-eastern part of Iran. Carbone monoxide in highly toxic for human health and natural ecosystems in metropolition districts especially due to high traffic and industrial activities. For this reason, it was decided to investigate and find out the high concentartion of Co pollutants in heavy traffic intersections of Kerman City. In this regards 21 heavy traffic squares and intersections were selected and the concentration of CO were measured. In the middle of each month during the year, sampling and measurement were scheduled three times at daily times according 7-12 am; 12-16 and 16-20 pm. In each period, 12 samples of 5 minutes were collected and CO concentration for 1-hr was calculated. The results obtained indicate that the hourly mean concentrations were lower than WHO guidelines and also lower than measurements of 1989, which has already done. In spite of more cases and higher populations, natural gas distribution was the cause of decline in CO concentrations.