Acacia trees are of great importance to Bedouin life where they provide a stable browse for their flocks, especially for camels and goats where their pods and leaves showed good level of digestible protein and energy. The present study was undertaken in Wadi Mandar, South Sinai, Egypt. Observations were made for insects and araneids causing seeds damage of six Acacia tortilis trees (subspecies tortilis and raddiana) during four months in 2002 (April to July). The highest month of pods infestation was in June. Insects were represented by a number of 10 genera from 4 insect orders: Coleoptera, Diptera, Hemiptera and Hymenoptera. The highest number of individuals belonged to order Coleoptera (Family: Bruchidae). In addition two parasitic wasp species were recorded. On the other hand, two species of spiders were also found (family: Thomisidae and Salticidae). The total number of infested seeds was 2603 with a percentage value of the infested seeds to healthy ones was 64.34 %. The degree of infestation of pods results showed that the most common degree of infestation in all months was the mildly infestation (1–3 pores or holes per pod). The results of the severity of infestation of seeds revealed that the highest rank in the infested seeds was the completely destroyed seeds. A conclusion drawn from this study is that Acacia tree in our desert ecosystem is exposed to a considerable insects and spiders threats which makes it need more attention to maintain this great wealth.