Background: Cold therapy, or cryotherapy, is the application of low temperature to reduce pain and swelling, and it is used widely in routine practice to ease the pain and anxiety of venipuncture. This systematic review and meta‐analysis evaluated its effect on venipuncture pain and anxiety, together with postprocedure heart rate. Methods: This systematic review and meta‐analysis was registered on PROSPERO and included randomized controlled trials (RCTs) of cryotherapy during venipuncture, with no geographical restrictions. We searched PubMed, the Cochrane Library, Embase, Scopus, Web of Science, and ClinicalTrials.gov, which returned 502 records, and screened them in Rayyan. Sixteen RCTs met the eligibility criteria, and 14 provided data suitable for pooling. Pain was the primary outcome, and anxiety was the secondary outcome, with postprocedure heart rate as an additional outcome. Risk of bias was assessed with the Cochrane ROB2 tool. Analyses were carried out in R using the meta and metafor packages with a random‐effects model and the Hartung–Knapp adjustment. Because the trials used several pain scales, the standardized mean difference (Hedges g) was the primary effect measure. Subgroup analyses and random‐effects meta‐regression (age, application duration, and needle gauge) were used to explore heterogeneity, and small‐study effects were examined with the funnel plot, Egger’s test, and trim and fill. Results: The quantitative synthesis pooled data across 14 RCTs. Cryotherapy significantly reduced venipuncture pain (primary effect measure: SMD [Hedges’ g] = −1.23; 95% CI: −2.03 to −0.44; p = 0.005; expressed on a common 0–10 pain scale for interpretability: MD = −1.97 points, 95% CI: −2.98 to −0.96) although substantial heterogeneity was observed (I 2 = 93%). Subgroup analysis revealed that clinical condition significantly modified treatment response ( p = 0.038), with maintenance hemodialysis patients experiencing the largest benefit (SMD = −1.87). Meta‐regression identified needle gauge as a notable variance modifier (coefficient = −0.16 per gauge unit; p = 0.070), suggesting enhanced relative relief with finer needles. Cryotherapy yielded no statistically significant effect on anxiety (SMD = −0.19; 95% CI: −1.49 to 1.10; p = 0.59; I 2 = 75%), but was associated with a small reduction in postprocedure heart rate (MD = −2.58 bpm; 95% CI: −4.20 to −0.96; p = 0.015; I 2 = 0%). According to GRADE criteria, certainty of evidence was rated low for pain and heart rate, and very low for anxiety. Conclusion: Cryotherapy may reduce venipuncture pain, with the largest possible effects in hemodialysis patients, but it does not appear to reduce procedural anxiety. High heterogeneity, the impossibility of blinding, and low certainty of evidence mean that the findings should be read with caution, and the pooled pain effect may vary in practice. Larger, standardized trials are needed to define its clinical role.