Abstract The long-path photometer previously described was adapted for photometric microtitrations. The instrument was tested employing several types of titrations. Turbidimetric titrations of silver with chloride and of barium with sulfate did not yield good results. However, the following titrations gave excellent results down to the levels indicated in parentheses: iron(II) with permanganate (0.4 ppm), zinc with EDTA in the presence of excess Zincon (6 ppm), copper with EDTA in the presence of excess SNAZOXS (9 ppb !), and calcium with EDTA in the presence of excess arsenazo III (100 ppb). The last of these titrations gave good results although a blank of about 25% of the actual volume of titrant required was encountered.