A Ca-selective film electrode that allows 1 × 10-4-1 × 10-1 M Ca(II) to be determined in the pH range 5.5-13 has been developed on the basis of l,8-bis[2-(piperidineiminomethine)phenoxy]-3,6-dioxaoctane. The slope of the electrode response is 22 ± 3 mV/pc. The electrode was used for the potentiometric indication of the end point in the titration of Ca(II) with EDTA solution at pH 12-13 in the presence of sodium, potassium, and magnesium. © 1998 MAHK Hayka/Interperiodica Publishing.