The applications of vibrational spectroscopy to study the structure of polysaccharide and hydrocolloid ingredients are presented. Vibrational spectroscopy, including infrared (IR) and Raman spectroscopies, has been used for both qualitative and quantitative analysis of starches and other polysaccharide ingredients. Some structural characteristics of starch and nonstarch polysaccharides have been studied using various vibrational spectroscopic techniques. The degree of substitution (DS) in modified polysaccharides can also be determined by IR and Raman spectroscopy, replacing the traditional wet chemistry procedure. Vibrational spectroscopy has also been used to determine protein structural characteristics and to monitor conformational changes under different buffer conditions. Conformation is an important parameter affecting the functional properties of protein hydrocolloids, and extensive conformational changes may occur during food processing and interactions with other food ingredients. Fourier transform (FT)–mid‐IR spectroscopy has been used to obtain information on protein structure and protein–protein and protein–lipid interactions. The extent of modification in modified food proteins and the effect of these modifications on protein conformation have been monitored by Raman spectroscopy. These modified polysaccharide and protein hydrocolloids, with enhanced gelling, thickening, and emulsifying properties, are important hydrocolloid ingredients for a wide variety of food products.