The development of bacterial resistance to the available antibiotics and increasing popularity of traditional medicine has led researchers to investigate the antibacterial compounds in plants. One traditional medicine in that category is turmeric (Curcuma longa) which belongs to the ginger (Zingiberaceae) family. Its major constituents are fat soluble, polyphenolic pigments known as curcuminoids which give turmeric its unique aroma, flavour and medicinal properties. In this study, the in-vitro antimicrobial activity of the aqueous extract of Curcuma longa rhizome was investigated against standard strains of Staphylococcus aureus (ATCC 6571), Escherichia coli (ATCC 25922), Salmonella typhi (ATCC 6539), Pseudomonas aeruginosa (ATCC 27853) and Bacillus subtilis (6633) using the agar well diffusion method. Different concentrations of the extract were prepared ranging from 12.5 mg/ml to 400 mg/ml. Staphylococcus aureus was more sensitive to the extract with zones of inhibition ranging from 13 mm to 27 mm. Escherichia coli was the least sensitive with zones of inhibition ranging from 7 mm to 22 mm. Mean Minimum Inhibitory Concentration (MIC) values were as follows: S. aureus (12.5 mg/ml), E. coli (25 mg/ml), S. typhi (50 mg/ml), P. aeruginosa (50 mg/ml) and B. subtilis (12.5 mg/ml). Qualitative phytochemical screening revealed the presence of alkaloids, flavonoids, saponins, glycosides and tannins.