A total of 336 patients suspected of having allergic contact dermatitis underwent patch testing at our institution from August 2000 to February 2005 using the European Standard Series by Chemotechnique Diagnostics composed of 25 allergens. The cutaneous lesions were located on the hands (46.2 percent), feet (29.1 percent), arms (25.5 percent), legs (21.0 percent) and trunk (15.9 percent). Patch test results showed that 303 (90 percent) had one or more positive patch test reaction. The most frequent positive reactions were to nickel sulfate (42 percent), potassium dichromate (30.7 percent), cobalt chloride (25.5 percent), parabens (22.5 percent) and fragrance mix (18.65 percent) while the least frequent were Tixocortil-21-pivalate (33 percent), Quarternium -15 1.0 percent pet (3 percent), Budesonide (2.7 percent) and Quinolone mix 6.0 percent pet (2.7 percent). In this study the most frequent relevant sources for nickel sulfate were keys/keychains, costume jewelry, coins and watches. For potassium dichromate the top sources were adhesives, detergents and leather. The most common sources for cobalt chloride were zippers/buttons and jewelry. For parabens the relevant sources were food products and cosmetics while for fragrance mix these were cosmetics and fragrances.