Quality control test was conducted to assess the post-shipment quality of commercially available P. persimilis from 3 different companies supplying this product to growers in Canada. These 3 products were all delivered by courier in less than 24 hours to SCPFRC, London, on 18 November, 1998 and kept in a $12^{circ}C$ and 70% RH cabinet. Spider mite, Tetranychus urticae, as prey of predatory mites was reared on the kidney bean plants in the incubator. The proportion of dead mites to living mites varied considerably among the 3 different companies. From the 3 companies only one male was detected in 173 mites observed. On day 5, 82.4% of the mites were still alive from company B. Whereas, only 62.5% and 38.1 % were alive from companies A and C, respectively. All the products from 3 companies attained a mean of more than 10 eggs per female over 5 days. These data indicated that P. persimilis from 3 companies reached to the quantity, sex ratio, survival, fecundity, and predation as recommended in the IOBC guidelines.