We estimate the X-factor of the Colombian electric power distribution sector in the period 2010-2019 by means of stochastic frontier analysis. Our estimates suggest an overall average X-factor equal to -1.6%, where just 3 out of 23 network operators (NOs) have average positive X-factors. In addition, we found that the average efficiency in the period is equal to 32.8% in this sector. This suggests that there is gap for improvements in the sector.