Context: For several decades, warfarin has been considered the mainstay anticoagulant for patients who require long-term prevention or treatment of thromboembolic disorders in outpatient settings. Hospital and community pharmacists––with adequate knowledge level and counseling skills––can play a significant role in improving warfarin therapy. Aims: The aim of this study was to assess the hospital and community pharmacists’ warfarin therapy knowledge and counseling practices in the eastern province of Saudi Arabia. Materials and Methods: A cross-sectional study was conducted for 2 months. A self-administered questionnaire was designed focusing on warfarin mechanism of action, indications, safety profile, management of toxicity, monitoring, drug/food interactions, and patient education. The questionnaire was distributed among a random sample of hospital and community pharmacists in the Eastern Province of Saudi Arabia. Results: One hundred and fifty-three pharmacists participated in the study; ninety-seven of them were hospital-based (63.4%), whereas the remaining were community pharmacists. Participant’s mean years’ of experience was 5.67. In terms of the percentage of right answers, hospital pharmacists showed significantly better warfarin therapy knowledge than community pharmacists ( P = 0.026). The percentages of right answers were 31.3% for drug/food interactions, 49.9% for safety profile/management of toxicity, 53.3% for patient education, and 58.2% for monitoring warfarin safety/efficacy. Neither the participants’ educational level nor their duration of experience had a significant correlation with the percentage of right answers ( P = 0.22 and 0.61) Conclusion: Inadequate knowledge and inappropriate practices were encountered among study participants, especially community pharmacists. Therefore, specialized training of pharmacists about warfarin therapy management is essential to optimize therapeutic outcomes and prevent complications.