The biodegradation of three phthalic acid esters (PAEs) - dimethyl phthalate (DMP), dibutyl phthalate (DBP) and di(2-ethyl hexyl)phthalate (DEHP) - was studied in a garden soil. The degradation rates of DMP and DBP were greater than that of DEHP under aerobic conditions. Anaerobiosis created by flooding greatly retarded the degradation of the three PAEs. The results suggest that microflora, especially bacteria, are actively involved in the degradation of the three phthalate esters.