Macro invertebrates are most commonly used for biological monitoring of aquatic ecosystems. The present study aimed to evaluate changes of aquatic macro invertebrates community according to seasonal fluctuations and habitat structures at Wadi Al-Arj, Taif, Kingdom of Saudi Arabia. Three sites have been chosen for study. Two samples were taken twice monthly along a period of one year, from the beginning of February 2012 to the end of February 2013. During the sampling period some environmental factors (air and water temperature, pH and TDS) were measured. Sites showed significant differences in water pH and the total dissolved salts (TDS). The composition of invertebrate community was 17 taxa in site II and site III while in site I was 20 taxa. Many of the collected invertebrates have significant differences among sites. The abundance of collected invertebrates has monthly variations. Statistical analyses showed no significant differences among sites in total abundance, taxa richness and Shannon diversity at the studied sites. It was noticed that these variables showed different patterns of monthly variations.
