A total of 22 X-ray bursts were observed with the SAS-3 X-ray Observatory from NXB 1837 + 05. Eighteen bursts were observed during a seven-day period in 1976 July. The burst intervals were highly irregular, which is a unique behaviour among burst sources studied so far. The associated steady X-ray source is almost certainly SerX-1 (3U1837+04). Changes in the ‘steady’ flux of this source by factors of 2 were observed; however, they were not correlated with the burst intervals in the way observed by Clark et al. for the source in NGC 6624. Neither was there any correlation between the integrated burst flux and the burst intervals as observed for the rapid burster MXB 1730–335 (Lewin et al.). Four bursts were detected in 1976 August during a 32-hr observing period. At that time, the bursts seemed to occur at regular intervals of ~ 6.3 hr.