Phenytoin-induced gingival overgrowth (PIGO) is a common complication of the continuous use of medications. This paper presents a case of PIGO hindering oral function and compromising oral hygiene and aesthetics, which was treated with a combination of nonsurgical and surgical periodontal therapies. A 39-year-old male patient was referred for dental treatment with several complaints, especially upper and lower gingival overgrowth that hindered speech and swallowing. Generalized deep probing pockets and bone loss were detected. Diagnosis of gingival overgrowth associated with phenytoin and chronic periodontitis was established. The treatment plan consisted of conservative therapy with education on oral health, motivation and meticulous oral hygiene instruction in combination with scaling and root planing. During the revaluation period, a marked reduction in the clinical parameters was noted, particularly probing pocket depth reduction. Surgical therapy for removal of gingival overgrowth was also performed to achieve pocket reduction. Supportive periodontal therapy was proposed and the patient is currently under follow-up for 4 years. Management of PIGO may be obtained by the use of periodontal procedures combined with good oral hygiene and periodontal supportive care.