Frost (1987a) proposed an algorithm for estimating the number of missing osteons that correspond to observed osteon population densities (OPD). Such an algorithm should allow more accurate estimates of bone remodeling rates for skeletal remains for which in vivo labeling is not possible. In order to validate the algorithm, it was tested on an autopsy sample of 44 ribs. Estimates of activation frequency. (RC) and bone remodeling rate (Vf,r,t) using the new algorithm are in reasonable agreement with age-matched tetracycline-based values. Although mean values for activation frequencies (RC) and bone formation rate (Vf,r,t) generated by the algorithm were generally lower, they fell below 1 standard error for only an age category that included all ages above the 5th decade. It is now appropriate to apply the algorithm to archaeological skeletal remains. © 1994 Wiley-Liss, Inc.