This paper presents a critical review of dosimetric monitoring practices during Chernobyl cleanup from 1986 to 1990. Dosimetric monitoring is considered in time evolution with respect to legislative background (including dose limits), methods of dose assessment, and coverage of workers with radiation monitoring programs as well as availability of data on individual doses of liquidators. Four large independent dosimetry services (Administration of Construction No. 605, Chernobyl Nuclear Power Plant, Production Association "Combinat," and the troops) had operated in Chernobyl covering different cohorts of cleanup workers with dosimetric monitoring of variable quality and comprehension. Extremes in this range were presented by the highly professional dosimetry service of the Administration of Construction No. 605 (USSR Ministry of Medium Machinery), which had provided total coverage of workers with high quality individual thermoluminescent dosimeter monitoring, and military (troops of the USSR Ministry of Defense) who had received the least precise group dosimetry, which, however, had covered the whole population of military cleanup workers. The main groups of liquidators are considered from the point of view of completeness and quality of their dosimetric data. Main gaps in dosimetric data and limitations of existing dose records are identified. The issues of evolution of dose limits and problems of monitoring internal and beta exposure are considered from the point of view of significance of these components and the need for missing information.