Use of plastics is increasing day by day, even though the hazardous effect of long-term use is recently known. Fragmented plastic contents have been reported in food and air. Exposure to such microfragments has adverse effects on human and marine species. Micro- and nanoplastics may exert toxicity and alter immune response. Plastics can adsorb chemicals and pollutants owing to the presence of endogenous additives. However, the lack of internationally accepted definitions of micro- and nanoplastics is major hindrance in the development of standardized methods and quality assurance. The current chapter deals with the classification of fragmented plastics, their effect on aquaculture and seafoods, their impact on human health, method of analysis, detections, identification and quantification techniques and their loopholes. Lastly, conclusions and future perspective in this area are discussed.