Early diagnosis of colorectal cancer (CRC) is crucial for successful treatment and mortality reduction. In this regard, blood-based tests play an indispensable role. Current research is focused on molecules actively secreted by tumor cells into small extracellular vesicles (EVs). This four-phase study included 613 CRC patients, 446 controls, and 120 precancerous lesions. High-throughput transcriptome profiling of small EVs was performed on samples from 100 CRC patients and 50 controls, followed by extensive validation using reverse transcription quantitative polymerase chain reaction. Diagnostic panels were developed via logistic regression and further characterized by enrolling samples from gastric cancer patients, CRC patients before/after surgery, and samples of tumor tissues/adjacent mucosa. We identified 17 molecules significantly elevated in CRC, with the highest levels in metastatic cases. Additionally, seven of them differentiated controls from precancerous lesions. Two diagnostic panels were developed, enabling early CRC detection with high sensitivity and specificity, outperforming the fecal occult blood test. Furthermore, six molecules were differentially expressed between tumor tissue and mucosa, while seven EV-enriched molecules decreased significantly after surgery. These findings highlight EVs as key reservoirs of CRC-associated molecules and a promising source of biomarkers.