The nickel-cadmium battery (commonly abbreviated NiCd) is a popular type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes.

The principal advantages of NiCd over other rechargeable types is lower weight for a given quantity of stored energy, good charging efficiency, small variation in terminal voltage during discharge, low internal resistance, and non-critical charging conditions. They can be used in place of regular batteries in most applications

Sealed NiCd cells may be used individually, or assembled into battery packs containing two or more cells. Small NiCd dry cells are used for portable electronics and toys, often using cells manufactured in the same sizes as primary cells. When NiCds are substituted for primary cells, the lower terminal voltage and smaller amperehour capacity may reduce performance as compared to primary cells.

Specialty NiCd batteries have a niche market in the area of cordless and wireless telephones, emergency lighting, model airplanes, as well as power tools.

With a relatively low internal resistance, a NiCd battery can supply high surge currents. This makes them a favourable choice for remote controlled electric model aeroplanes, boats, and cars, as well as cordless power tools and camera flash units. Larger flooded cells are used for aircraft starting batteries, electric vehicles, and standby power.

NiCd batteries contain cadmium, which is a toxic heavy metal and therefore requires special care during battery disposal. In the United States, part of the price of a NiCd battery is a fee for its proper disposal at the end of its service lifetime. In the European Union, the Restriction of Hazardous Substances Directive (RoHS) bans the use of cadmium in electrical and electronic equipment products after July 2006, though NiCd batteries are not restricted.

Cadmium, being a heavy metal, can cause substantial pollution when landfilled or incinerated. Because of this, many countries now operate recycling programs to capture and reprocess old NiCd batteries.