This paper introduces the R package CDM for cognitive diagnosis models (CDMs). The package implements parameter estimation procedures for two general CDM frameworks, the generalized-deterministic input noisy-and-gate (G-DINA) and the general diagnostic model (GDM). It contains additional functions for analyzing data under these frameworks, like tools for simulating and plotting data, or for evaluating global model and item fit. The paper describes the theoretical aspects of implemented CDM frameworks and it illustrates the usage of the package with empirical data of the common fraction subtraction test by Tatsuoka (1984).