Association between Crohn's disease (CD) and lupus nephritis is very rare and, to the best of our knowledge, it has been described only once. We report here a clinical case of CD occurred in a young woman 8 years after a diagnosis of lupus nephritis according to clinical, laboratory and histological criteria. CD was unresponsive to steroids and immunosuppressants and, therefore, the patient was treated with anti-tumour necrosis factor alpha monoclonal antibody (Infliximab). This therapy led to the remission of both CD (50% of Crohn's Disease Activity Index--CDAI--decrease) and lupus nephritis (disappearance of pyuria in absence of infection, significant increase of serum albumin and improvement of renal function tests). The immunological background of both diseases has to be taken into account to explain either the association of the two disorders or the therapeutic response. Moreover, this clinical case confirms and extends the concept that in patients with CD a more accurate detection of autoimmune associated disorders is required.