Background: Reciprocal drug interactions are among the most common causes of adverse drug reactions. We investigated the incidence and related risk factors associated with mutual drug interactions in relation to prescriptions written in the neurology wards of two major teaching hospitals in Shiraz, southern Iran. Methods: Data was collected from hand-written prescriptions on a daily basis. Mutual drug interactions were identified using Lexi-Comp 2012 version 1.9.1. Type D and X drug interactions were considered as potential drug-drug interactions. The potential risk factors associated with drug-drug interactions included the patient’s age and gender, number of medications and orders, length of hospitalization and the type of neurological disorder. To determine potential drug-drug interactions, relevant interventions were suggested to the physicians or nurses and the outcome of the interventions were documented. Results: The study comprised 589 patients, of which 53% were males and 47% females, with a mean age of 56.65±18.19 SD years. A total of 4942 drug orders and 3784 medications were prescribed among which 4539 drug-drug interactions were detected, including 4118 type C, 403 type D, and 18 type X. Using a logistic regression model, the number of medications, length of hospitalization and non-vascular type of the neurological disorder were found to be significantly associated with potential drug-drug interactions. From the total interventions, 74.24% were accepted by physicians and nurses. Conclusion: Potentially hazardous reciprocal drug interactions are common among patients in neurology wards. Clinical pharmacists can play a critical role in the prevention of drug-drug interactions in hospitalized patients.