Osteoarthritis (OA) is a growing welfare problem for dogs and a challenge to manage for the clinician, and most therapeutic options aim to control pain. In a randomized, double-blinded, placebo-controlled, 2-way, 2-period crossover study, we aimed to evaluate the use of Blood Cell Secretome (BCS) administrated intra-articularly, with or without the combination with triamcinolone, in dogs with bilateral hip OA. BCS is an acellular orthobiologic containing anti-inflammatory and anabolic proteins produced from the patient's own blood through extended coagulation in a defined environment. Fifteen dogs were initially assigned to a BCS group (BCSG, = 5), a triamcinolone group (TG, = 5), or a combination group (BCS+TG, = 5). All had bilateral hip OA. After a 180-day follow-up, the crossover was performed with BCSG ( = 7) and BCS+TG ( = 7). BCSG received a single intra-articular administration of 3 mL of Blood Cell Secretome, and BCS+TG received BCS plus 0.5 mL of triamcinolone acetonide (40 mg/mL). The volume in BCSG was corrected to 3.5 mL with saline. In all patients, both hips were treated. For treatment follow-up, a copy of the Canine Brief Pain Inventory (divided into pain interference score-PIS and Pain Severity Score-PSS), Liverpool Osteoarthritis in Dogs (LOAD), and Canine Orthopedic Index (COI, divided into function, gait, stiffness, and quality of life) was completed on days 0, 8, 15, 30, 60, 90, 120, 150, and 180. Results were analyzed with the Mann-Whitney U test, effect size, and Kaplan-Meier estimators, followed by the log-rank test. was set at <0.05. Patients of the sample had a mean age of 9.6 ± 2.9 years and a body weight of 29.2 ± 3.9 kg. Seven hips were classified as severe osteoarthritis, and eight were classified as moderate. No differences were found between groups at T0. Significant differences were observed in PSS scores at +8d, with BCS+TG exhibiting better results. PIS, PSS, LOAD, stiffness, and function scores were also lower in BCS+TG from +15 to +60d. The two groups showed similar improvements from +90 to +120d. Kaplan-Meier estimators showed that dogs in BCS+TG showed clinically-important differences for longer, despite a positive result in BCSG. The intra-articular administration of BCS alone was able to improve the overall condition of OA patients. Its combined use with triamcinolone acetonide lead to a faster and longer-lasting improvement in pain scores.