A commercially available fluoride electrode has been evaluated for use in routine analysis. The electrode has been shown to yield good results, without the necessity for careful control of temperature, etc. As such, it is extremely useful in surveillance studies, and in routine analyses generally. Tests on samples showed that aluminium interfered seriously. An improved ionic buffer containing CDTA is recommended in order to control this interference, since both citrate and EDTA had only limited applicability. With CDTA present, reliable fluoride analyses were possible in the presence of up to 5 mg/l aluminium. © 1969.