Aims Mycoplasma genitalium causes a common, sexually transmitted bacterial infection. This study assessed the detection of M. genitalium in stored urine samples to understand the impact of sample storage on M. genitalium detection. Methods Aliquots of M. genitalium-positive urine (n = 20 patients) were stored at either room temperature (22 degrees C) or 4 degrees C, without a preservative. At weekly intervals, samples were tested using the commercial test ResistancePlus MG (R) (SpeeDx (R), Australia). We report the analysis at 1 week, an acceptable collection-to-test turnaround time, with further analysis over 5 weeks to illustrate degradation trends. Results After storing at 4 degrees C, the proportion of specimens that remained positive for M. genitalium was 100% after 1 week and 95% after 4 weeks. Storage at 22 degrees C led to more rapid decline in detection in the first 4 weeks, with 95% detected after 1 week and 85% at 2 weeks onwards. At 5 weeks, samples stored at both temperatures had an 85% M. genitalium detection rate, with increase in crossing points (Cq) of 0 center dot 72 (95% confidence interval (CI) 0 center dot 01-1 center dot 43; P-trend = 0 center dot 027) at 4 degrees C, and 1 center dot 75 ((95% CI 0 center dot 79-2 center dot 71), P-trend <0 center dot 001) at 22 degrees C. Conclusions Urine samples stored without preservative, and unfrozen, retained high M. genitalium detection levels over the short term (up to 5 weeks). To minimize degradation, storing at 4 degrees C is recommended. Significance and Impact of the Study There is little known about the stability of clinical samples for M. genitalium detection. This study found that a high proportion (85-100%) of samples are still suitable for M. genitalium detection after storage for up to 5 weeks.