In recent years, queueing models with Markovian arrival process have attracted interest among researchers due to their applications in telecommunications. Such models are generally dealt with matrix-analytic method which appears to be powerful analytically despite the fact that it has numerical difficulties. However, analyzing such queues with the method of roots is always a neglected part since it was assumed that such models are difficult to analyze using roots. In this paper, we consider a bulk service queue with Markovian arrival process and analyze it using the method of roots and present a simple closed-form analysis for evaluating queue-length distribution at a post-departure epoch in terms of roots of the characteristic equation associated with the MAP/R $^{(a,b)}$ /1 queue, where R represents the class of distributions whose Laplace–Stieltjes transforms are rational functions. We also obtain queue-length distributions at arbitrary epochs. Numerical aspects have been tested for a variety of arrival and service-time (including matrix-exponential (ME)) distributions and a sample of numerical outputs is presented. We hope that the proposed method should be useful for practitioners of queueing theory.