We study three manpower allocation problems in labor-intensive cellular manufacturing, for which mathematical programming formulations were already developed and computer tested but no computational complexity analysis is provided in the literature. We present very efficient new solution procedures for two of these problems and prove that the third problem is NP-hard in the strong sense and that it can be solved efficiently for special cases. Solutions of the studied problems can be used for solving more general manpower allocation and cell loading problems in labor-intensive cellular manufacturing.