Gender variation in lung function is more evident in lung volumes and capacities involving forced muscle contraction. Few studies have been done to demonstrate the reason behind gender difference in lung function and none was conclusive. This study aimed to investigate gender difference in respiratory muscle power and its correlation with the lung function test parameters. The study was performed in two groups of University students 25 males and 25 females matched for age, height and weight at National Ribat University in Khartoum, Sudan during January 2011. The two groups were of the same ethnic class, socio-economic status and perfect health. Lung Function Tests including Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), and Peak Expiratory Flow (PEF) were performed using a digital spirometer and maximum inspiratory and expiratory pressers (MIP &MEP) as indicators for respiratory muscle power were measured using a Respiratory Pressure Meter (MicroRPM).For MIP test: after fitting the mouth piece the subject was asked to exhale to residual volume then perform a forced inhalation against the MicroRPM with as much effort as possible for as long as possible. For MEP test: the subject was asked to inhale to total lung capacity then perform a forced exhalation against the MicroRPM as maximum and long as possible. To ascertain a best value, each test was repeated 3 times. Data were analyzed using SPSS software and independent t- test was used to compare the mean difference in results. The mean age (year), height (cm) and weight (Kg) of males group under the study were 20.32 ± 0.80, 167.88 ± 2.99 and 61.36 ± 5.87 respectively while in females group were 20.00 ± 0.64, 165.96 ±4.36, 61.88 ± 7.15 respectively. Mean FVC(L), FEV1(L) and PEF(L/min.) in males group were 4.09 ± 0.51, 3.68 ± 0.45 and 561.60 ± 70.10 respectively, while in females group FVC, FEV1 and PEFR were 2.93 ± 0.45, 2.80 ± 0.36, 389.60 ± 46.68 respectively. Statistically significant sex difference was found in the three lung function test parameters (p<0.001). Mean MEP and MIP (cm/H2O) were 143.48 ± 23.83 and 111.92 ± 15.05 respectively in the males group compared to 87.72 ± 20.02 and 73.08 ± 12.35 respectively in the females group with statistically significant sex difference (p < 0.001). A significant positive correlation between respiratory muscle power indicators (MEP or MIP) and lung function parameters (FEV1, FVC and PEF in both sexes (p < 0.001). In conclusion: gender variation in lung function is likely explained by gender difference in the power of the respiratory muscles. MEP and MIP measuring could be applied to study sport variation in lung function and low lung function in conditions affecting muscle power.