Laelaps echidninus and Laelaps nuttalli are two important species of gamasid mites in both indoor and outdoor cultivated habitats in western Yunnan, China. The common dominant rodent hosts of these two gamasid mites are Rattus flavipectus, Rattus norvegicus and Rattus nitidus. Spatial patterns of the two species of gamasid mites among the individuals of their dominant hosts were studied in this paper. Iwao's linear regression method and a significance test of random deviation for the method were used. In the light of Iwao's method, two regression equations were established. The equation for L. echidninus is M^* = 4.97 3.05 M (a = 4.97, b = 3.05) and other for L. nuttalli is M^* = 2.93 4.81 M (a = 2.93, b = 4.81). Both a and b in these two equations are considerably higher than 0 and 1, the border values for determining spatial pattern of populations. The F values are 13.30 (F >F_0.01(2,8),(2,8), P > 0.01) for L. echidninus and 10.22 (F >F_0.01(2,8), P<0.01) for L. nuttalli respectively in the significance test of random. The spatial patterns of L. echidninus and L. nuttalli among the individuals of their dominant hosts are of aggregated distribution.