For early diagnosis of children with neurodevelopmental disorders, neurological assessment during early infancy and follow-up examinations are essential. However, to make the neurological assessment effective, some knowledge regarding the examination procedures and interpretation of the results is required. There have been many articles on the neurological assessment of early infants, but ones that clearly delineated its diagnostic significance have been surprisingly few. Based on our own experience and the literature, in this review we will discuss the diagnostic significance of neurological assessment of early infants, including of primitive reflexes (crossed extensor reflex, suprapubic extensor reflex, heel reflex, Galant response, asymmetric tonic neck reflex, plantar grasp response, and Babkin reflex), involuntary movements (ankle clonus and tremor), and Vojtas postural reactions. Neurological assessment of these reflexes is simple and useful for early detection of infants at high risk for a neurodevelopmental disorder that might later develop.