Dehydration can impact the general population but it is particularly detrimental for athletes, due to their physical performance requirements. Although fluids in general contribute to meeting hydration needs, some beverages aid in the rehydration process more than others. The Beverage Intake Questionnaire (BEVQ-15) is a food frequency questionnaire (FFQ) that can rapidly assess habitual beverage intake; this FFQ has been validated in children and adults. However, no beverage consumption questionnaire has been validated in athletes. In addition to monitoring fluid intake, hydration status can be assessed through urinary and blood indices. Urine color (UC) has been utilized as a practical hydration biomarker in several populations. However, this biomarker has not been validated among the general population of collegiate athletes. The first study (n=58): formulated a novel whey-permeate-based beverage to promote hydration and assess its sensory characteristics in the general population. The overall acceptability of the beverage was lower than the control beverage, according to a 9-point Likert scale (x̅ = 4.5 – 4.9 and x̅ = 6.7, respectively). The second study (n=120): evaluated the comparative validity and reliability of the BEVQ-15 and UC within NCAA Division 1 collegiate athletes. Associations were noted between the BEVQ-15 and multiple 24-hr dietary recalls (reference method) for total beverage fl oz and kcal (r=0.41 and r=0.47, p<0.05, respectively). There were associations between athlete's UC and urinary specific gravity (USG; hydration biomarker) rated by athletes and researchers (r=0.67 and 0.88, p<0.05, respectively). Lastly, a systematic review was performed to evaluate original research addressing the validity of UC as a hydration biomarker in the adult population more broadly, including athletes and older adults. Eleven of 424 articles met inclusion criteria, and the available research generally reported significant correlations between UC and other hydration indices (r=0.35-0.93). However, limitations in existing research were evident. Although the BEVQ-15 may be a valid beverage intake assessment method in collegiate athletes, additional modifications were identified which could improve its validity. Future work includes re-evaluating the validity and reliability of the BEVQ-15 specifically modified for athletes, as well as assessing the sensitivity of this FFQ to detect changes in beverage intake. / Doctor of Philosophy / Drinking adequate amounts of fluids is important for maintaining normal bodily functions. When body water losses exceed fluid intake, dehydration may result, which can lead to numerous consequences such as headaches, dizziness, decreased mental focus, and fatigue. An athlete, who has high physical demands, may experience these negative consequences as well as muscle cramps, increased strain on the heart, and decreased athletic performance. Some beverages can replenish lost fluids better than others, due to their electrolyte (i.e. sodium, potassium, magnesium) content. This may include whey-permeate based beverages. In order to prevent dehydration, it is important to monitor fluid consumption and fluid losses. A beverage intake questionnaire (BEVQ-15) can be used to quickly assess usual beverage intake. Studies have shown that this questionnaire is accurate in children, adolescents, and adults. However, there are currently no validated methods for usual habitual beverage intake in athletes. This dissertation evaluated the taste of a new whey-permeate hydration beverage, and the accuracy and test-retest reliability of the BEVQ-15 within NCAA Division 1 collegiate athletes and found positive results. Measurements in urine and blood can be also be used to assess hydration status, but some of these methods are more expensive and less practical for daily use in real-world settings. Urine color (UC) has been studied as a hydration indicator, but this dissertation is the first to evaluate the accuracy and reliability of this method within a diverse group of collegiate athletes, in a real-world setting. Our results suggest that UC is a simple and reasonably accurate hydration assessment method when compared to another urinary assessment method. Nonetheless, there is limited research which has studied this topic. Future work can address methods to improve the effectiveness of these approaches for maintaining and evaluating fluid intake and status in the collegiate athletic population.