Meniscal injuries are a common challenge in orthopaedic surgery. Depending on their location and the patient's age and functional needs, they can be treated either conservatively or surgically. A surgical approach can consist of arthroscopic meniscectomy or meniscal suture. The latter is the treatment of choice in case of lesions involving the red-red or red-white areas of the meniscus, especially for young high-demanding patients. We report here our experience with the repair of longitudinal meniscal tears using the all-inside technique with the Fast-Fix™ 360 Meniscal Repair System (Smith & Nephew Endoscopy, Andover, MA). We retrospectively evaluated 20 consecutive cases of longitudinal meniscal tears. In 4 cases, concomitant ACL rupture was diagnosed and treated alongside the meniscal repair. All patients underwent periodic clinical evaluations. At the latest check-up, their functional outcomes were rated according to the Tegner-Lysholm Knee and KOOS scoring scales. The mean Tegner-Lysholm Knee score was 84.85 (44-100) and the mean KOOS score was 88.58. No failure or major complications were observed. Furthermore, a negative statistical association was observed between age at surgery and the post-operative Tegner-Lysholm Knee score (coef. = -1.01189 [-1.942073,-0.0817063], p = 0.035). This relation, independent of gender, meniscus involved, eventual associated ACL reconstruction, and chondral injury, suggests that functional outcomes worsen with increasing patient age. Our results suggest that the arthroscopic all-inside suture is both safe and effective in cases of longitudinal meniscal tear, considering the good post-operative functionality and low rates of local complications and surgical failures.