This study aimed at isolating filamentous bacteria from the activated sludge samples of a full- scale municipal wastewater treatment plant in Dubai and studying their physiological and biochemical characteristics. Fluorescent in situ hybridization technique (FISH) was applied to identify filamentous bacteria pure culture isolates. In total, sixteen filamentous bacteria were successfully isolated and maintained on various culture media. Ten gram positive filamentous bacteria were successfully identified as nocardioform actinomycete using nocardioform group specific probes in FISH analysis. Most of the isolates were shown to utilize different carbon sources like glycerol, maltose, fructose etc. The optimum growth of most of the isolates was found to be at 27° C and neutral pH, however a few isolates were able to grow at 47° C and acidic pH. Overall results indicate that filamentous bacteria isolated in this study were quite diverse in their physiological and biochemical characteristics and could be of significance for further studies to establish their taxonomic status and possible role in foam formation and its control in the activated sludge process.