The purpose of this study was to examine the effect of gender in the relationship between time limit at the minimum velocity that elicits maximal oxygen consumption (TLim-v O2max) and three swimming economy (SE) related parameters: the energy cost corresponding to v O2max (Cv O2max), the slope of the regression line obtained from the relationship between energy expenditure ( ) and corresponding velocities in a incremental test (Cslope) and the ratio obtained by the mean value and the velocity mean value of the incremental test (Cinc). Each subject of two gender groups - 11 male and 12 female swimmers - performed an incremental test for v O2max assessment and an all-out TLim-v O2max test. TLim-v O2max, v O2max, Cv O2max, Cslope and Cinc averaged, respectively, 244.6±56.5s, 1.45±0.04m.s-1, 15.9±2.2J.kg-1.m-1, 35.0±4.8J.kg-1.m-1 and 14.3±2.4J.kg-1.m-1 in the male group and 248.0±60.5s, 1.33±0.04m.s-1, 14.3±1.8J.kg-1.m-1, 35.7±6.4J.kg-1.m-1 and 11.5±1.5J.kg-1.m-1 in the female group. An inverse correlation was found between TLim-v O2max and Cslope for the entire group (r=-0.78, p<0.001) and for each gender group (r=-0.90, p<0.001 and r=-0.61, p<0.05, for female and male respectively), confirming that SE is a very important performance-influencing factor. Complementarily, despite the relationship between energy cost and TLim-v O2max efforts is evident in each gender, the TLim-v O2max tests performed by the female swimmers seem to depend more on their own SE than on male swimmers.