Biological aspects of solitary versus group rearing of Theridion spinitarse Cambridge (Araneae: Theridiidae) on Spodoptera littoralis Boisd. Larvae under 30°C and 60-70% R.H. were considered. Developmental durations did not differ between the two situations. Males and females reached maturity after the fifth spiderling. Life cycle was 60.89, 63.33, 55.1 and 62.1 days for males and females under solitary and group rearing, respectively. Adult longevity, lifespan, fecundity of female and food consumption were recorded. Results indicated that group rearing favored better biological aspects than individual rearing under same conditions as well as female's specific data. Pre-oviposion period was shorter in group rearing compared with solitary one (i.e. 12.2 versus 25.73 days, respectively). Oviposion period was longer for group rearing with higher fecundity per female (i.e. 62.3 versus 41.82 days). Fecundity was 158.30 versus 99.00 eggs/ female, respectively. It was concluded that better emulation of natural conditions for the organism results in more accurate biological aspects data.