Electrochemical sensor for simultaneous microextraction and electrochemical determination of anticancer drug imatinib were developed by the dendrimer assisted reduced graphene oxide adsorbent. The steps of the method are as follows: Initially, the fabricated nanocomposite was deposited on the surface of the pencil graphite lead. Then the modified pencil graphite electrode carefully placed inside a piece of polypropylene hollow fiber using an ionic liquid as the carrier. The working electrode was used in conjunction with an auxiliary electrode, and a reference electrode in a three electrode system. The study was explored using the Taguchi experimental design method. For this purpose, the parameters including the type of dendrimer, dendrimer and reduced graphene oxide amounts, dendrimer to reduced graphene oxide ratio in hollow fiber and the sample solution pH, were optimized with a Taguchi L-25 orthogonal array (OA) design. The results were confirmed by the ANOVA. Calibration curves were found to be linear in the range from 0.01 to 200 mu molL(-1), with two linear ranges, first from 0.01 to 10 mu mol L-1 and second from 10 to 200 mu mol L-1, with a detection limit of 7.39 nmol L-1. The selectivity of the optimized procedure was examined in the presence of two anticancer drugs and some common excipients to monitor the interference effect. In addition, the comparison between hollow fiber-modified pencil graphite sensor and modified pencil graphite electrode demonstrated that the newly designed sensor showed that the fiber sensor offers a wider linear range, more sensitivity, and low detection limit.