We present an overview of the successes and challenges still faced in the detection of NO, O(2)(*-) and ONOO(-) in biological media. We provide a full discussion on the electrochemical analyses of each of these species and we summarise the significant research contributions towards the development of sensors for individual and simultaneous detection of these species. We emphasize the importance of understanding the potential interferents in developing such sensors. We show that significant advances have been made with regard to the detection of NO in biological media leading to the development of marketable NO sensors, though there is room for improvement in terms of interferences. A brief outlook into the future perspectives of the use of a multi-electrochemical array sensor for simultaneous detection of NO, O(2)(*-) and ONOO(-) is presented.