p16 is one extensively studied marker in gynecological pathology. However, its routine application in the diagnosis of squamous intraepithelial lesions of the uterine cervix may present difficulties for the general pathologist. The aim of the present study was to examine a series of 100 cervical biopsies/LEEP specimens, with detailed HPV-typing, for patterns of p16 immunoreactivity and possible correlations with morphology and HPV types. Four patterns of immunopositivity were recognized, according to the distribution of positively stained cells, and these correlated to lesion grade. A review of the pertinent literature concerning p16 immunoreactivity in squamous intraepithelial lesions and nonneoplastic epithelia of the uterine cervix is included in an effort to summarize the existing data and the remaining questions at both the practical and theoretical level.