This work aimed to study the biodegradation dynamics of plasticized cellulose acetate samples (etrols) with different content of plasticizers. Isophthalic acid dimethyl ester and orthophosphoric acid tributyl ester were used as plasticizers. The targets of the study also included assessing the effect of the plasticizers' content on the degradation rate. The biodegradability of plasticized cellulose acetate samples was assessed by measuring the weight loss after exposure to active soil. For the experiment, an active soil of the following composition was prepared: garden soil - 89 vol. %, distilled water - 10 vol. %, microbiological preparation "Tamir"- 1 vol. %. All etrols samples showed a tendency to decomposition in active soil. The rate of sample degradation varied significantly. The highest degradation rate in active soil was shown by a sample containing 16 wt. % tributyl phosphate and 22 wt. % dimethyl isophthalate, as good as ertols sample containing 8 wt. % tributyl phosphate and 14 wt. % dimethyl isophthalate. The expected decomposition time of these samples in the active soil for 90% is 599 and 732 days, respectively. Changing of dimethyl isophthalate content did not affect the degradation rate. Withal the content of tributyl phosphate in the etrols induced a significant effect on the samples' weight loss. The consequence of the plasticizers' content on the weight loss rate for 145 days of exposure in the active soil is described by the equation y=-4.76+1.25•Z 1+1.49•Z2-0.04•Z 12-0.086•Z22+0.000141 where Z1 is the content of dimethyl isophthalate, Z2 is the content of tributyl phosphate. © Published under licence by IOP Publishing Ltd.