Periods and Light-Curves of Variable Stars in NGC 121

82 photographs of the globular cluster NGC 121 on the outskirts of the Small Magellanic Cloud, covering a total range of 9 years but mostly concentrated in three consecutive seasons, are used to derive periods and light-curves of 5 variables within $$1^{\prime}$$ of the cluster. Of these, three are short-period variables (periods between 0.50 and 0.64 days) of Bailey a and b type with the usual relations between period, amplitude and shape of light-curve. The other two, among the reddest and brightest of the cluster-stars, have periods of 140.2 and 112.4 : days. The light-variations are presented in the form of step-estimates on a “ basic ” sequence. Four other short-period variables have been found on the plates which are too far from the cluster to be members. They are sufficiently faint to be regarded as possibly the first instance of RR Lyr variables in the general field of the Small Magellanic Cloud.