This present research aims to clarify the relative sexual size dimorphism of Centrobolus (Cook) in 18 congenerics. Millipedes illustrated reversed sexual size dimorphism (SSD) where females were larger than males; and break Rensch’s rule as this dimorphism increased with body size. SSD was calculated in 18 species of the genus Centrobolus and illustrated was illustrated in 2 regressions: (1) male versus female SSD and (2) SSD and body size. The allometric equation for Centrobolus was (1) Å·=0.00051X0.01071. SSD ranged from 0.63–2.89 (1.55±0.63; n≥18) and was not negatively correlated (R=0.70485; P=0.00109; n=18 spp.) with a volumetric index of body size ranging from 284–2683 mm3 (1097.89±638.06; 18). The rejection of the rule appears consistent in some animals.