To analyze the factorial structure and psychometric properties of the Spanish adaptation of the AEQ, and to validate it by reporting relevant pain-related variables, which were not investigated in the original study. One hundred and fifty Spanish patients diagnosed with chronic back and neck pain were referred by physicians from different pain clinics in Spain; all the patients filled out the questionnaires at their clinic. A series of principal components analyses (PCA) was performed to develop the Spanish version of the AEQ. Reliability and validity were also calculated. The PCAs revealed five fear-avoidance scales (Kaiser-Meyer-Olkin measures were between .60 and .88, and Bartlett’s tests were significant, p < .01): the Depression scale (DS), Anxiety scale (AS), Catastrophizing scale (CS), Helplessness/hopelessness scale (HHS), and Avoidance of Social and Physical Activities scale (ASPAS), and three endurance-related responses scales: Pain Persistence Behaviour and Distraction scale (PPDS), Ignoring Pain scale (IPS), and Humor scale (HS). All the scales showed high internal consistency (α > .73) and suitable validity (p < .05). New results associated with pain-related cognitive/affective and behavioural responses are discussed. This instrument will probably help clinicians to identify Spanish patients at a high risk of chronicity and to develop treatments tailored to the different profiles in order to improve secondary and tertiary prevention in back and neck pain.