To determine the prognostic CT and MR imaging features of extranodal non-Hodgkin lymphoma in the head and neck region. The clinical data and CT and MR imaging features of 59 patients with histologically confirmed extranodal non-Hodgkin lymphoma in the head and neck region were retrospectively reviewed. Subjects included 27 male and 32 female patients between 13 and 81 years of age, with a mean age of 60.3 years. The clinical outcomes were categorized according to whether relapse or metastasis occurred within 2 years after therapy. The association between the clinical outcome and radiologic factors including tumour size, margin, shape, local tumour invasiveness, regional lymph node involvement, number of involvement sites, and contrast enhancement patterns was determined using univariate and multiple logistic regression analysis. Radiologic factors including tumour size, margin, shape, and local tumour invasiveness were associated with poor clinical outcomes, as determined by univariate analysis (P < 0.05). Only the lesion margin category (ill-defined) remained an independent risk factor for clinical outcome in multivariate logistic regression analysis, with an OR of 8.14 (P < 0.05). Ill-defined margin of the primary lesion was indicative of unfavourable survival outcome for patients with extranodal non-Hodgkin lymphoma of the head and neck region. Tumour size, margin, shape and local tumour invasiveness were prognostically relevant. Tumour margin was an independent risk factor for clinical outcome. Ill-defined margin of primary lesion was indicative of unfavourable survival outcome.