Background: It has been suggested that small metastatic lymph nodes (LN) detected after initial surgery in patients with differentiated thyroid cancer (DTC) can be managed with active surveillance (AS). However, there is still concern regarding the clinical outcomes of these patients. The main aims of our study were: i) to assess the frequency of growth and the need of additional treatment in a group of low-risk patients with LN recurrences selected for AS, and ii) to determine predictive factors of LN progression. Methods: We retrospectively reviewed 856 clinical records from our DTC patient’s database (May 2010-Jan 2022). Eighty patients had suspicious cervical LNs on consecutive ultrasounds (US) after initial surgery, but we included 50 patients with cytological confirmation of metastatic disease and at least 12 months follow-up. Exclusion criteria: any LN ≥2 cm or multiple LNs ≥1.5 cm in size, proximity to vital structures, PET-positive disease (SUV ≥5), aggressive histology, and distant metastasis. Patients were followed with thyroglobulin (Tg) and thyroglobulin antibodies (TgAb) measurements on suppressive therapy and neck US every 6-12 months. LN growth was defined as an increase of ≥3 mm in any of its diameter. Results: A total of 50 patients had a median age of 41 years (range, 18-75). Most patients were women (80%) and had classical papillary thyroid cancer (86%). The mean size of the LNs was 10.1 ± 4.4 mm. After a median follow-up of 29 months (range, 12-144), 12 patients (24%) had an increase in size of the metastatic LN, 7 (58%) of whom were surgically removed. None of these 7 patients had a structural incomplete response at the end of follow-up. The only variable that predicted an increase in LN size was a rise in Tg levels ≥0.5 ng/ml (p = 0.016). Based on a multivariate analysis, patients with increase in Tg levels ≥0.5 ng/ml had a significantly higher chance of developing LN growth (OR 16.2, 95% CI: 1.5-120.2, p = 0.020). The median progression-free survival rate was 6.6 years (95% CI: 5.6-9.5). Conclusion: AS of small LNs could be a feasible alternative to immediate surgery in properly selected low-risk patients.