It is well known that during their course from arteriole to venule the capillaries in skeletal muscle branch and anastomose repeatedly (Krogh, 1919; Hammersen, 1968). There appears, however, to have been little previous attempt to quantitate the extent and pattern of capillary branching, although Eriksson and Myrhage (1972) reported that the capillaries of the tenuissimus muscle of the cat were 1.015 mm long, with branches to adjacent capillaries every 0.20 mm along their length. We have studied the branching pattern of these interconnections in the sartorius muscle of the frog, vasodilated by injection of papaverine and perfused with a silicone elastomer (Microfil). Each terminal arteriole gave rise to an average of 2.71 ± 1.34 (SD) capillaries. Each capillary had a mean of 3.44 ± 1.84 (SD) interior branch points. More than 90% of capillary branchings were simple divergent or convergent bifurcations, the included angle having an approximate mean value of 60° in each case. The initial branchings were mainly divergent, but the proportion of convergences increased linearly at successive branchings along the path. Some branches anastomosed with a capillary path to which the vessel had been connected previously. The incidence of such “rejoins” rose to 35% by the third and fourth branches, maximizing interaction between adjacent capillaries and maintaining each group of vessels as a fairly distinct microvascular unit. From these numerical data, plus measurements of path and segment lengths, realistic models of the capillary network have been synthesized. The fact that the anastomoses are so extensive suggests that they may play a key role in maintaining oxygenation of muscle tissue.