In adults, cellulitis is usually caused by group A streptococci and Staphylococcus aureus. However, in patients with underlying disease, it may be caused by other organisms, such as Acinetobacter, Clostridium septicum, Enterobacter, Haemophilus influenzae, Proteus mirabilis or Escherichia coli. We report three cases of cellulitis of the lower legs where E. coli was the causative bacterial organism. It is important to suspect E. coli as a causative organism if blistering cellulitis occurs, especially in patients with underlying diseases.