The purpose of this article is to consolidate data collected from a variety of sources that have permitted calculations of the rates of growth of human neoplasms. These sources include Fischel State Cancer Hospital (Columbia, MO); Mallinckrodt Institute of Radiology, (St. Louis, MO); Roentgen Diagnostic Institute, Allmanna Sjukhuset (Malmo, Sweden); University of Louisville (Louisville, Kentucky); University of Heidelberg (Heidelberg, Germany); and St. Luke's Hospital (St. Louis, MO). Included in the data are laboratory measurements of cell replication rates. All gross measurements were made either on imaging studies or with a centimeter scale for surface or palpable neoplasms. Data have been reported for breast and pulmonary cancers and metastases of many types, melanomas, skeletal sarcomas, benign and malignant colonic neoplasms, and isolated cases of less frequent neoplasms. Related cytokinetic measurements by tritriated thymidine labelling, bromodeoxyuridine labelling, S-phase fraction from DNA flow cytometric analysis, and mitotic indices are discussed. The various mathematical formulae applicable to the analysis of the collected data and the determination of rates and patterns of growth are included. Also considered are the clinical implications of these data and the importance of ever better knowledge on the cytokinetics of human cancer. Prior studies on the evolution of insight into this field are cited and discussed. The authors conclude that a more accurate quantification of the growth rates of human cancer is essential for understanding the biological variance of human cancers seen clinically. © 1995 Wiley-Liss, Inc.