Total antioxidant capacity (TAC) of some Rosmarinus officinalis L.(rosemary) extracts was investigated by an “in batch” analytical method based on chemiluminescence (CL). This method is based on a CL reaction between luminol and hydroxyl radicals generated by the hydrogen peroxide in the presence of Co (II) ions complexed with ethylene diamine tetraacetic acid (EDTA) disodium salt, according to a Fenton-type reaction. The method allows for TAC determination in 1 x 10-5–2.5 10-3 moles L-1domain of gallic acid concentration and with a relative standard deviation (RSD)= 2.53%(n= 10) for 8 x 10-4 M gallic acid concentration. The TAC values determined for the analyzed rosemary extracts ranged between 1.6 and 4.58 grams of gallic acid equivalents/100 g dw plant. The employed analytical method was verified by applying the standard addition method and a good precision was established.