A Co2+ ion-selective membrane sensor has been fabricated in a poly(vinyl chloride) matrix based on a recently synthesized 3,3'-(dodecylazanediyl)bis(N-(2-(2-aminoethylamino)ethyl)propanamide) (DAEP) as a neutral carrier, sodium tetraphenylborate (NaTPB) as an anionic excluder, and dioctylphthalate (DOP) as a solvent mediator. The electrode exhibits a Nernstian response over a wide concentration range [(6.58.10(-7) to 1.0.10(-1)) M] between pH 2.5 and 8.5, and the limit of detection is 6.82.10(-8) M. The response time of the sensor is about 5 s, and it can be used over a period of 5 months without any divergence in potential. The proposed membrane sensor revealed good selectivity for Co2+ over a wide variety of other metal ions. The electrode has been used as an indicator electrode in the potentiometric titration of Co2+ with ethylenediaminetetraacetic acid (EDTA) and the direct determination of Co2+ in wastewater from the electroplating industry.