The review considers ionophore-based electrochemical sensors (ion-selective electrodes). In general the progress in the field is subdivided in two distinctly different trends: (1) an extensive development (enhancing of the list of ions whose concentration can be selectively measured with the corresponding new sensors) and (2) an intensive development (improvement of the analytical capabilities of already known sensors). Recent articles (mostly published after the year 2000) describing the ionophore-based ion-selective electrodes are classified and briefly characterized from this viewpoint.