In this work, the effect of flame redardant additives on the creep behavior of ABS polymer was studied. Three ABS/flame redardant systems were compared with the bare ABS samples, namely: a commercial additive system based on bromine (Br-ABS), which served as a basis for comparison, and two systems recently developed, using tannic acid (TA) and ammonium polyphosphate (APP) bio-retardants. The results obtained in the creep tests showed that the commercial additive did not change the creep behavior in relation to ABS without additive. On the other hand, the results indicated that creep behavior was reduced when APP was incorporated into ABS and increased when TA was added. Experimental data from creep tests were used to evaluate the viscoelastic behavior of the four groups of materials. ABS had its behavior adequately represented by the Stretched Burgers model, as well as ABS with bromine-based additive, although with a low correlation coefficient. The model that best described the behavior of ABS with ammonium polyphosphate (APP) was also the modified Burgers model (Streched Burgers model). For ABS with tannic acid (TA), the model that best described the behavior was the standard linear solid.