¡@The shell utilization of two sympatric hermit carb species was studied in shallow waters of Kaohsiung and Pingtung, southern Taiwan. Principal components, canonical variates and univariate analysis was used to compare three major variables of shell resource: species, size, and shape between species and sites. The regression between crab and shell and shell adequacy index (SAI) revealed that two species shared the same resource which had shell size limitation in the field had different pattern. Shells used by Diogenes rectimanus were larger than those uesd by D. nitidimanus of same size. But the utilization pattern was the same under a shell sufficient condition in the laboratory, suggesting that there was no resource partitioning or competition between these two species. The size of shell composed a continuous morphological overlap at four different sites and shown a good consistency with crab size. This revealed the utilization of crabs in different size selected different shells and suggested a status of sufficient resource utilization. Although the shell resource were highly similar, but different composition of shell species and other factors could caused variances in shell size and shape between four sites, and caused crab size divergence among different populations.