During the last decades (dissolved-air) flotation has found several applications in water and wastewater treatment. Flocculation is generally required in advance for a satisfactory separation and a membrane process is often applied downstream. Examples from the literature given in the present review include heavy metals, textile dyes, food, paper industry, oily effluents, laundry wastewaters, sludge etc. and are accompanied by typical laboratory results. Among the used techniques, the process known as electroflotation (or electrolytic flotation), which often incorporates electrocoagulation, was particularly focused in this paper due to certain advantages it offers; this process is certainly suitable for small-scale applications.