Four lines of chickens selected for divergence in body weight followed by selection for obesity or leanness within each body weight line were used as a genetic model to determine the relationship of blood pressure and obesity. Forty females, 10 of each line, and 20 males, 10 from the heavy-weight obese and 10 from the light-weight obese, were used. Direct measurements of blood pressure were obtained from the left brachial artery of seven-month old birds. Systolic, diastolic, and mean blood pressures were recorded in this study. The systolic, diastolic, and mean blood pressure for the light-obese and light-lean females did not differ significantly; likewise, no difference was found for these three parameters in the heavy-obese and heavy-lean females. However, the blood pressures in the light-obese and light-lean lines were significantly higher than the heavy-obese and heavy-lean lines. Also, the blood pressures of the light-obese males were higher than those of the heavy-obese males; both male lines exceeded the females of the two respective lines.