Subcutaneous rehydration is an optional infusion route in hospitalized older adults. This meta-analysis sought to compare the effectiveness of subcutaneous versus intravenous (IV) fluid administration to reverse mild-to-moderate dehydration in hospitalized older adults. A literature search was performed. No restrictions were imposed regarding language. Three randomized clinical trials conducted with patients 60 years of age or older treated with subcutaneous or IV rehydration were included, with a total sample size of 197 patients. Controlled quasi-randomized and crossover trials were excluded. The primary end point was reversal of dehydration. Secondary end points were patient satisfaction and frequency of adverse events (eg, cellulitis, edema, phlebitis, erythema, hyponatremia, and pain). Both treatments were effective in rehydrating the patients within 48 hours, with no statistically significant difference between the groups. Subcutaneous fluid administration effectively reversed dehydration while protecting against phlebitis. Since the quality of evidence was considerably low, further multicenter randomized clinical trials of efficient methodological quality should be conducted to consolidate the body of evidence.