SummaryThis case report discusses the clinical signs, diagnostic findings, treatment and outcome of a 6‐year‐old Italian Warmblood gelding referred for evaluation of a chronic unilateral ocular mucopurulent discharge that had been ongoing for several months. Dacryocystorhinography and computed tomography dacryocystography (CT‐DCG) allowed the identification of a neoformation associated with tooth 206 connected to a cystic lesion occupying the ipsilateral ventral nasal concha. It is likely that both lesions caused stenosis of the nasolacrimal duct and secondary recurrent ocular discharge. Once the 206 tooth had been surgically removed, a histological diagnosis of nodular hypercementosis associated with a small cystic lesion was made. In this case, CT‐DCG was extremely important in identifying the source of the ocular discharge and guiding the surgical planning for tooth removal. A follow‐up telephone conversation with the owner 6 months postoperatively reported that the horse had not shown further ocular discharge.