Few studies have reported the incidence or prevalence of cracked teeth with pulpal involvement. No attempts have been made to evaluate the prevalence or clinical predictors for intrapulpal cracks. The purpose of this study was to investigate the prevalence of intrapulpal cracks in first and second mandibular molars and to determine if clinical findings are predictive for the existence of intrapulpal cracks. First and second mandibular molars (190) requiring non-surgical root canal treatment at the VCU Graduate Endodontic Practice between February 15, 2013 and August 15, 2013 were analyzed retrospectively. Teeth were transilluminated, stained, and inspected for intrapulpal cracks using a dental microscope. Data gathered included: demographics, subjective and objective information regarding the chief complaint to include bite stick test, transillumination, probing depths greater than 4mm, existing restorations, and diagnosis. Chi-square and logistic regression were performed (p<0.05). The prevalence of intrapulpal cracks in first and second mandibular molars combined was 9% (17/190, 95%CI= 5.7% to 13.9%). The prevalence was 7% for 1st molars and 13% for 2nd molars. There was no statically significant difference in the prevalence between first and second mandibular molars. Individual characteristics predictive for the existence of intrapulpal cracks were age, probing depth greater than 4mm, transillumination and a positive Tooth Slooth™ test (all p<0.05). Staining of the pulp chamber after access identified only one of 17 intrapulpal cracks. Staining of the pulp chamber did not significantly increase the ability to identify intrapulpal cracks. Neither diagnosis, sex, nor existing restorations were significant predictors for intrapulpal cracks. Probing depth greater than 4mm, age over 40 and a positive Tooth Slooth™ test were conjointly significant for predicting intrapulpal cracks.