Longus colli calcific tendinitis is a secondary inflammation caused by the deposition of hydroxyapatite crystal in the longus colli tendon. It causes acute neck pain, limitations of neck movement and swallowing pain. The symptoms are usually resolved in 1 to 2 weeks when treated with analgesics and anti-inflammatory medications. A 45-year-old man visited our hospital with a complaint of severe neck pain and stiffness despite 3 days of therapy with loxoprofen prescribed by the first doctor he visited. Computed tomography (CT) imaging showed small calcification localized at the anterior C1-C2 level and a low density area in the retropharyngeal space without ring enhancement. A definitive diagnosis of longus colli calcific tendinitis was made. Cimetidine (100 mg twice daily) was added to his loxoprofen dosage. His neck pain improved remarkably in one day after commencing cimetidine treatment. And 3 days after starting the treatment his neck could be moved without limitation. On day 11 of the treatment, CT imaging showed reduction in the calcified deposit, and he was already completely asymptomatic. Cimetidine is an H2 receptor antagonist, and has been used for treatment of gastric ulcers. Furthermore, many studies have reported the treatment efficacy of cimetidine on calcific tendinitis of the shoulder. However, few studies have yet been reported on the longus colli tendon. Our report suggests that cimetidine may be effective against calcific tendinitis of the longus colli tendon as well as the shoulder. Because of the severe pain associated with this condition, patients often take large doses NSAIDs and need to be prescribed an anti-ulcer agent. In such a case, cimetidine may deserve consideration.