A radar system is considered in which the detection and tracking functions are completely integrated. The system parameters are then chosen to minimise the mean-square tracking error of the integrated system. An analytical result is applied which allows the impact of detection errors on tracking accuracy. This was the first known result of this nature, as usually detection and tracking are viewed as independent functions, with the detection process regarded as perfect in assessing tracking accuracy. The result is partly empirical, and herein we test it in a digital-computer simulation. The performance objective of the integrated detection and tracking system is to minimise the mean-square tracking error, subject to the constraint that the probability of a track not being lost exceeds a prescribed value. We also consider multitarget environments and show how to allocate radar resources such that the average tracking error is minimal. Using a digital-computer simulation, our results show that considerable performance improvement results when radar resources are optimally allocated relative to a scheme where every target shares the radar resources on an equal basis. An electronic scanning capability for the radar is assumed throughout our work. A shortcoming of the research is the assumption that radar returns, when detected, are always associated with the true track. However, false alarms as a degradation in the track-measurement process are included in our work.