Quantitative neuromuscular block (NMB) assessment is an internationally recognised necessity in anesthesia care whenever neuromuscular blocking agents are administered. Despite this, the incidence of residual neuromuscular block and its associated major respiratory morbidity and mortality remain unacceptably high considering its preventable nature. Recent surveys show that quantitative NMB assessment is not consistently employed by anesthesiologists. Availability, price and practical concerns are some of the factors determining this phenomenon. Clinically assess and validate an Android cell phone application conceived specifically for NMB Monitoring in the anesthesia setting. Twenty-two adult ASA I to III patients scheduled to undergo elective surgical procedures under general anaesthesia requiring administration of a neuromuscular blocking agent were included. After anaesthesia induction, the grade of neuromuscular block was assessed at multiple independent time-points by paired comparison of the train of four (TOF) Ratios obtained by a Stimpod™ accelerometer and the currently developed application. Accelerometric measurements were made at the patient’s hand after retrograde supramaximal stimulation of the ipsilateral ulnar nerve. TOF-ratios were subjected to bias analysis with 0.001 as the a priori established clinical significance cut-off. The difference between the two methods averaged 0.0004 (95% limits of agreement: ± 0.12), with 83.3% of the differences being under 0.05. This average inter-method difference was not significantly different than the a priori hypothesized difference cut-off of 0.001 (p = 0.78). Lin’s concordance correlation coefficient and Pearson’s correlation were both of 0.98. The custom developed Android application proved accurate for diagnosis of residual neuromuscular block.