The review paper considers ionophore-based electrochemical sensors (ion-selective electrodes). As a whole, progress in the field is subdivided into two distinctly different paths. These are (i) the extensive development: enlargement of the number of ions which concentration can be selectively measured with the respective novel sensors, and (ii) the intensive development: enhancement of analytical capabilities of already known sensors. Recent articles (mostly - published after the year 2000) devoted to ionophore based ion-selective electrodes are classified and briefly characterized from this viewpoint.