Previous studies about the influence of body dimensions on running economy have not compared athletes specialized in different competition events. Therefore, the purpose of the present study was to assess the influence of body mass (mb) and height (h) on the energy cost of running (Cr) in 38 highly trained male runners, specialized in either marathon (M, n = 12), long middle-distance (5000 - 10000 m, LMD, n = 14) or short middle-distance (800 - 1500 m, SMD, n = 12), and to assess possible differences in body dimensions for each event. Subjects performed a progressive maximal exercise on the treadmill to determine oxygen uptake (V˙O2) at different submaximal velocities and maximal oxygen uptake (V˙O2max). Cr was calculated from V˙O2 measurements. LMD runners had significantly higher mean Cr (0.192 ± 0.007, 0.182 ± 0.009, and 0.180 ± 0.009 ml O2 × kg-1 × m-1 for LMD, M and SMD, respectively) and V˙O2max (74.1 ± 3.7, 68.5 ± 2.9 and 69.7 ± 3.4 ml × kg-1 × min-1). Cr correlated with h (r = -0.86, p < 0.001) and mb (r = -0.77, p < 0.01) only in the SMD group. In conclusion, these data suggest that highly trained distance runners tend to show counterbalancing profiles of running economy and V˙O2max (the higher Cr, the higher V˙O2max and vice versa), and that anthropometric characteristics related with good performance are different in long-distance and middle-distance events.