The aim of this article is to meta-analyse published data about the detection rate (DR) of fluorine-18-fluorodeoxyglucose ((18) F-FDG) positron emission tomography (PET) and PET/computed tomography (CT) in the evaluation of patients with marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT). A comprehensive literature search of studies published through February 2014 was performed. Pooled DR of (18) F-FDG PET or PET/CT including 95% confidence intervals (95% CI) was calculated on a per-patient-based analysis. Twenty studies including 376 patients with MALT lymphoma were selected. The pooled DR of (18) F-FDG PET or PET/CT was 71% (95% CI: 61-80%). A significant difference between the DR of PET/CT (69%; 95% CI: 61-80%) and that of PET alone (73%; 95% CI: 60-84%) was not demonstrated. A better DR of (18) F-FDG PET or PET/CT in bronchial (94%; 95% CI: 85-99%) and head-and-neck (90%; 95% CI: 78-98%) MALT lymphomas compared with gastric (62%; 95% CI: 46-77%) and ocular (49%; 95% CI: 36-63%) MALT lymphomas was found. This meta-analysis demonstrates that MALT lymphoma is an (18) F-FDG-avid tumour in most of the cases, suggesting a potential clinical role of (18) F-FDG PET or PET/CT in the initial evaluation of these patients. In particular, the DR of (18) F-FDG PET or PET/CT is related to the primary site of the MALT lymphoma.