Background: Early neurological deterioration (END) is a prominent issue after recanalization treatment. However, few studies have reported the characteristics of END after endovascular treatment (EVT) as so far. This study investigated the incidence, composition, and outcomes of END after intravenous recombinant tissue plasminogen activator (IV rt-PA) and EVT of acute ischemic stroke, and identified risk factors for END. Methods: Medical records of patients who received recanalization treatment between January 1, 2014, and December 31, 2015 were reviewed. Patients were classified into IV rt-PA or EVT group according to the methods ofrecanalization treatment. The END was defined as an increase in the National Institutes of Health Stroke Scale (NIHSS) >= 4 or an increase in la of NIHSS >= 1 within 72 h after recanalization treatment. Clinical data were compared between the END and non-END subgroups within each recanalization group. Results: Of the 278 patients included in the study, the incidence of END was 34.2%. The incidence rates of END were 29.8% in the IV rt-PA group and 40.2% in the EVT group. Ischemia progression (68.4%) was the main contributor to END followed by vasogenic cerebral edema (21. 1%) and symptomatic intracranial hemorrhage (10.5%). Multivariate logistic regression showed that admission systolic blood pressure (SBP) >= 160 mmHg (odds ratio [OR]: 2.312, 95% confidence interval [CI]: 1.105-4.837) and large artery occlusion after IV rt-PA (OR: 3.628, 95% CT 1.482-8.881) independently predicted END after IV rt-PA; and admission SBP >= 140 mmHg (OR: 5.183, 95% CL: 1.967-13.661), partial recanalization (OR: 4.791,95% CL: 1.749-13.121), and nonrecanalization (OR: 5.952,95% C: 1.841-19.243) independently predicted END after EVT. The mortality rate and grave outcome rate at discharge of all the END patients (26.3% and 55.8%) were higher than those of all the non-END patients (1.1% and 18.6%; P < 0.01). Conclusions: END was not an uncommon event and associated with death and grave outcome at discharge. High admission SBP and unsatisfactory recanalization of occluded arteries might predict END.