Introduction: To carry out ultrasound-guided cervical nerve root block (CNRB) safely, we investigated the frequency of risky blood vessels around the target nerve root and within the imaginary needle pathway in the actual injecting position. Methods: 30 patients (20 men, 10 women) with cervical radiculopathy who received ultrasound-guided CNRB were included in this study. We defined a risky blood vessel as an artery existing within 4 mm from the center of the target nerve root or located in the range of 2 mm above or below the imaginary needle pathway. Results: Using the color Doppler method, the frequency of a risky blood vessel existing around 4 mm from the center of the C5 nerve root was 3.3% (1/30), whereas it was 3.3% (1/30) for the C6 nerve root and 23.3% (7/30) for the C7 nerve root. Hence, the C7 level had more blood vessels close to the target nerve root compared to the C5 and C6 levels, but there was no significant difference (p = 0.0523). On the other hand, the frequency of a risky blood vessel existing within 2 mm above and below the imaginary needle pathway was 3.3% (1/30) for the C5 nerve root, whereas it was 3.3% (1/30) for the C6 nerve root and 10.0% (3/30) for the C7 nerve root. The C7 level had more blood vessels within the needle pathway compared to the C5 and C6 levels, but there was no significant difference (p = 0.301). Conclusions: To reduce the risk of unintended intravascular injections, more careful checking for the presence or absence of blood vessels at the C7 level using color Doppler is necessary.