Users of mobile telephones are exposed to radiofrequency radiation. One of the questions still open today is whether amplitude-modulated radiofrequency signals from digital phones exert specific bioeffects different from those of continuous (unmodulated) radiofrequency radiation. This paper reviews recent literature on the bioeffects of amplitude-modulated radiofrequency radiation, from cells to humans. The consistency of the results is discussed, and exposure parameters are compared to identify possible biologically active forms of amplitude modulation. Several studies have reported findings consistent with effects on the nervous system and cancer-related biological processes. However, the methods and exposure parameters vary widely, and no independent replications of the positive findings have been reported. The results available today fail to support the existence of well-defined modulation-specific bioeffects from exposure to radiofrequency radiation. Additional systematic studies are needed to identify possible reproducible modulation-dependent effects and biologically active modulation parameters.