We explored dynamic functional network connectivity (dFNC) in ALS and its correlation with disease severity. FNC states were determined by k-mean clustering, and state-specific FNC and dynamic indices (fraction time/mean dwell time/transition number) were calculated. ALS patients showed increased FNC between DMN-SMN in state 1 and between CCN-SMN in state 4. Patients remained in state 2 (showing the weakest FNC) for a significantly longer time and remained in state 1 (showing a relatively strong FNC) for a shorter time. A significant correlation was observed between ALSFRS-R and mean dwell time in state 2 and transition number.