Despite an emerging body of research on the institutional behavior and adjustment of delinquent males, there exists little information on the incarceration experiences of female delinquents. The present study explored the incidence, prevalence, and determinants of institutional misconduct among a sample of 139 serous and violent delinquent females sentences to State juvenile incarceration. Secondary data analysis was used for the present study. Data utilized were derived from information originally gathered by correctional staff during intake at a State Youth Correctional System (a pseudonym) and during an offender's entire incarceration through onsite diagnostic processes, staff observations, official records, and offender self-reports. Members of the study sample engaged in roughly 700 incidents of major misconduct and more than 12,000 instances of minor institutional misconduct during their incarceration. Results from negative binomial regression models examining four different types of institutional misconduct revealed that age at commitment, offense type, mental health status, and gang affiliation were related to the expected rate of misconduct, although this varied by misconduct typed. Institutionalization is not necessarily a period of desistance from offending for all delinquent girls. As institutional misconduct may impact post release recidivism, it is important to identify and intervene with at-risk juveniles during periods of incarceration. (Published Abstract) Tables, appendix, notes, and references