Abstract Introduction: Just recently, a novel autoantibody family consisting of anti-carbamylated protein (anti-Carp) antibodies is identified in RA patients. The aim of this study was to detect the presence of serum anti-Carp antibodies in RA patients RA patients and found out its relation to the clinical, radiological and musculoskeletal ultrasound assessment. Subjects and methods: This study was conducted on 80 persons, 50 patients with RA and 30 apparently healthy individuals representing the control group. Assessment of disease activity by DAS-28 and laboratory investigations included: Complete blood count, erythrocyte sedimentation rate, rheumatoid factor, C - reactive protein, serum level of Anti-Carp abs. Radiological evaluation by plain x-ray on both hands and MSUS examination by using 7- joint score was performed using grey scale (GS) and power Doppler (PD) assessment. Results: The mean age of the patients was 50.68 ± 11.69years, 39 females and 11 males, disease duration 7.08 ± 8.18 years. The number of cases positive for Anti-carp abs was higher in RA patients (32.0%) compared to controls (6.7%) (P = 0.009). DAS-28 was higher in negative RA group than positive one (P=0.011), there were no correlations between Anti-Carp abs and (CRP, Anti-CCP, DAS-28, ESR, GS synovitis and PD synovitis). Mean erosion score in RA with positive Anti-Carp abs (9.88±2.39) was higher than those with negative Anti-Carp abs (1.82±1.75) (P