Advanced polymers that exhibit volume increase when immersed in water or oil are known as swelling elastomers. They have been successfully used in recent years in downhole sealing applications in oil and gas drilling. Various case studies of use of swell packers can be found in published literature. However, these reports are usually targeted at only a couple of associated applications. To give a more holistic approach, the current paper describes many major applications of swelling elastomers in the petroleum industry. When undesirable zones are separated from production zones, it is called zonal isolation. Safeguarding production lines from water incursion is known as water shutoff. Techniques used to protect the wellbore from invasion of sand come under the umbrella of sand control. One of these is the use of sand screens, providing protection against plugging and wear of well equipment. Well completion is the series of tasks required to make the well productionready, the most important one being cementing. Well stimulation consists of enlargement of existing passages or formation of new ones for improved production. Swellable elastomers have been successfully employed in all of these applications, paving the way for improved or enhanced oil recovery in a relatively low-cost manner for long-term and effective solutions. These, and other applications, are discussed in the paper. This brief overview can be beneficial for petroleum students, field practitioners, researchers, and application designers.