The serum antibodies to N‐acetylgalactosaminyl GD1a (GalNAc‐GD1a) and other gangliosides as well as to Campylobacter jejuni were determined in 147 patients with Guillain‐Barré syndrome (GBS). We found a distinctive clinical pattern in patients with anti‐GalNAc‐GD1a antibodies compared with those without the antibodies, that is, lack of cranial nerve involvement (87% versus 38%), distal‐dominant weakness (80% versus 25%), and no sensory disturbance (73% versus 22%). The frequency of distal‐dominant weakness was significantly higher in patients with both C jejuni infection and anti‐GalNAc‐GD1a positivity (100%) than in C jejuni–negative/anti‐GalNAc‐GD1a–positive (25%), C jejuni–positive/anti‐GalNAc‐GD1a–negative (32%) and C jejuni–negative/anti‐GalNAc‐GD1a–negative patients (20%). Lack of cranial nerve involvement and sensory disturbance were found in most C jejuni–positive/anti‐GalNAc‐GD1a–positive and C jejuni–negative/anti‐GalNAc‐GD1a–positive patients, but not in C jejuni–positive/anti‐GalNAc‐GD1a–negative and C jejuni–negative/anti‐GalNAc‐GD1a–negative patients. Although the anti‐GM1–positive/anti‐GalNAc‐GD1a–negative patients mostly (75%) lacked cranial nerve involvement, distal‐dominant weakness (38%) and lack of sensory disturbance (13%) were infrequent. These results may indicate that (1) the combination of C jejuni infection and anti‐GalNAc‐GD1a antibodies, but not anti‐GalNAc‐GD1a, anti‐GM1, or C jejuni infection alone, is associated with a predominantly distal weakness, (2) the presence of anti‐GalNAc‐GD1a, rather than C jejuni infection or anti‐GM1 antibody, is associated with a lack of sensory disturbance, (3) both anti‐GalNAc‐GD1a and anti‐GM1 antibodies are independently associated with a lack of cranial nerve impairment. Ann Neurol 1999;45:758–768