BACKGROUND CONTEXT: Low early postoperative mobility (LEPOM) has been shown to be associated with increased length of hospital stay, complication rates, and likelihood of nonhome discharge. However, few studies have examined preoperative characteristics associated with LEPOM in adult spinal deformity (ASD) patients. PURPOSE: To investigate which preoperative patient characteristics may be associated with LEPOM after ASD surgery. DESIGN: Retrospective review. PATIENT SAMPLE: Included were 86 ASD patients with fusion of ≥5 levels for whom immediate-postoperative AM-PAC Basic Mobility Inpatient Short Form (6-Clicks) scores had been obtained. OUTCOME MEASURES: The primary outcome of this study was the likelihood of LEPOM, defined as an AM-PAC score ≤15, which is associated with inability to stand for more than 1 minute. METHODS: Significant cutoffs for preoperative characteristics associated with LEPOM were determined via threshold linear regression. Multivariable logistic regression was used to assess the impact of preoperative characteristics on the likelihood of LEPOM. RESULTS: LEPOM was recorded in 38 patients (44.2%). Threshold regression identified the following cutoffs to be associated with LEPOM: preoperative Patient Reported Outcomes Measurement Information System (PROMIS) scores of ≥68 for Pain, <28.3 for Physical Function, and ≥63.4 for Anxiety; preoperative Oswestry disability index (ODI) score of ≥60; and body mass index (BMI) of ≥35.2. On multivariate analysis, preoperative PROMIS scores of ≥68 for Pain (odds ratio [OR] 5.3, confidence interval [CI] 1.2-22.8, p=.03), <28.3 for Physical Function (OR 10.1, CI 1.8-58.2, p=.01), and ≥63.4 for Anxiety (OR 4.7, CI 1.1-20.8, p=.04); preoperative ODI score ≥60 (OR 38.8, CI 4.0-373.6, p=.002); BMI ≥35.2 (OR 14.2, CI 1.3-160.0, p=.03), and male sex (OR 5.4, CI 1.2-23.7, p=.03) were associated with increased odds of LEPOM. CONCLUSIONS: Preoperative PROMIS Pain, Physical Function, and Anxiety scores; ODI score; BMI; and male sex were associated with LEPOM. Several of these characteristics are modifiable risk factors and thus may be candidates for optimization before surgery. LEVEL OF EVIDENCE: III.