Many sets of diagnostic criteria have been proposed for neuroleptic malignant syndrome (NMS) but there is a lack of uniformity. No universally agreed criteria exist currently for research purposes, thus making comparisons across studies very difficult. Most of them have flaws and detect too many false-positives based on an over-inclusive definition. The estimates of incidence rates of NMS vary because of differences in the sensitivity threshold of the diagnostic criteria used. A new set of diagnostic criteria is proposed for research purposes. It is hoped that with this set of stringent research diagnostic criteria, future epidemiological, aetiological and treatment research studies on NMS will be more meaningful and comparable across studies. For routine clinical purposes, the clinicians should continue to use their clinical acumen, sound clinical judgement and discretion. To avoid premature aetiological closure and broaden treatment options, we also propose renaming this syndrome descriptively as drug-induced hyperthermic catatonia (DIHC).