Here an attempt has been made to discuss the application of Queueing theory as applicable to hospital registration services i.e. outpatient registrations, inpatient registrations and registration for ICU admissions. Then illustrates the practical application of queueing theory to a simple problem in manpower planning: how large staff is required to give adequate service for a central laboratory? The problem is simple enough to be amenable to an analytic solution, and the optimal solution arrived at by the use of queueing theory resulted in a considerable saving to the central laboratory studied. A model of the patient care process, based on queueing theory, is described and its parameters defined empirically for application to an ICU unit. The model is descriptive, with an output of expected waiting times for various priorities of patient demand. The waiting times so estimated constitute an index of the quality of nursing care and afford a means of predicting changes in quality with changes in staffing or inpatient load. The model facilitates investigation of the relationships among three factors: patient condition, nurses' activity priorities, and patient load per nurse.