Asparagus spears (Asparagus officinalis L.) are regarded as a healthy food due to their high fiber content, low-calorie content, and phytochemical content, such as vitamins, flavonoids, fructans, saponins, and cinnamic acids. Various studies have recognized these compounds for their antioxidant, anti-inflammatory, and anticancer properties. However, because a large portion of the underground (>30 Tm/ha), which includes roots, and the aerial (∼6 Tm/ha), which contains stems, leaves, and fruits, are wasted, asparagus cultivation and processing also generate a significant number of agri-food by-products. For asparagus growers, disposing of trash associated with the crop has become a major agronomic, financial, and environmental concern. The same nutrients and phytochemicals found in asparagus spears may also be found in asparagus roots and other by-products, according to observations made in recent years. As a result, these ingredients have great potential for use as food ingredients with exceptional nutritional value and health-promoting qualities. Hence, these inedible components ought to be viewed as food by-products that are valuable to several industries and support sustainable agriculture rather than just being a waste product of farming. Phenolic–polysaccharide complexes are abundant in the cell walls of asparagus, particularly following the hardening phase that occurs after harvest. This chapter thus explores the potential health benefits of bioactive phytochemicals from by-products of several species of Asparagus, including A. officinalis and A. racemosus, shedding light on utilizing agricultural waste to harness valuable compounds. Asparagus, a versatile vegetable, has gained attention not only for its culinary appeal but also for its rich phytochemical content. Furthermore, the practical applications of these bioactive compounds are considered, focusing on integrating asparagus by-product extracts into functional foods, nutraceuticals, or pharmaceutical formulations. This adds economic value to the by-products and aligns with a broader sustainability narrative in the food industry.