Objective. To evaluate the efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) (meloxicam) in acute nonspecific back pain (NSBP) depending on influence of clinical and anamnestic factors. Material and methods. The studied group included 2078 patients presented with an acute NSBP. All study subjects received meloxicam in a dose of 15 mg/day: 86.1% were given intramuscular meloxicam injections for the first 3—5 days and then switched to an oral meloxicam and 13.9% received an oral meloxicam throughout the therapy. Skeletal muscle relaxants (SMR) and oral or intramuscular group B vitamins were also prescribed to 52.3% and 17.4% of study patients, respectively. Pain was assessed on a 10-point numerical rank scale (NRS). The study assessed the rate of complete pain relief within a 2-weeks NSAID therapy. Results. Complete pain relief was achieved in 75.2% of study patients, mean period of treatment was 8.61±5.53 days. Adverse events were observed in 4.6% of patients. Age <65 years, first NSBP episode and a history of good response to NSAIDs were associated with better treatment outcomes. A severe baseline pain (NRS score ≥7), pain persistence at rest, at nights and, especially, sciatica were associated with poorer treatment outcomes. Co-administration of SMR and group B vitamins did not increase chances for pain relief compared to the NSAID monotherapy. Conclusions. Meloxicam in a dose of 15 mg/day is an effective and safe therapy for the treatment of acute NSBP. The analgesic effect of NSAIDs is higher in young patients, patients with the first episode of NBC and a good response to NSAIDs in history. Treatment of patients with NSBP in the presence of severe pain, maintaining pain at rest and at night, and in case of sciatica, requires special control and integrated treatment.