Measurements of the standing-crop and height of Spartina alterniflora on a Cananeia (SP) salt-marsh are presented. The standing- crop was 816 ± 187 g dry weight m-2 or 699 ± 164 g organic weight m-2 at the peak of the growing season. In the desnudated area the maximum grass height was found in July, when Spartina reached 130 cm. Spring, summer and winter were the beginning, the peak and the end of the growing season, respectively. Ash, Mg, Ca and Fe showed higher concentrations in dead rather than in living Spartina.