Patients with chronic low back pain (LBP) frequently demonstrate high scores for fear-avoidance beliefs and distress. We need better knowledge about fear-avoidance beliefs and distress in early stages of LBP. The objectives of this study were to compare the level of fear-avoidance beliefs and distress in patients with acute LBP to patients with chronic LBP, and to assess the relationship of fear-avoidance beliefs and distress to disability in acute and chronic LBP. Two different back pain groups including 123 patients with acute and 233 patients with chronic LBP were studied. Main outcome measures were Oswestry Disability Index and work loss. The scores for fear-avoidance beliefs and distress in patients with acute LBP were significantly lower than among patients with chronic LBP. The results of the multivariate regression analyses, adjusting for sociodemographic, pain and clinical variables, demonstrated that whereas fear-avoidance beliefs for physical activity and distress were significantly associated with the Oswestry Disability Index, fear-avoidance beliefs for work and distress were significantly associated with work loss. The associations showed the same pattern in acute and chronic LBP. In addition, several of the pain and clinical variables were significantly associated with the Oswestry Disability Index and fingertip-floor distance was associated with work loss. In conclusion, fear-avoidance beliefs and distress influence pain-related disability both in early acute and long-term chronic LBP. The results replicate previous reports on the association between pain experience, fear-avoidance beliefs, distress, and disability in chronic LBP, and extend the findings to patients at an early stage of acute LBP.