In the last few years, reports of pancreatic inflammatory diseases caused by immunological mechanisms and with good response to steroid treatment have increased. Although this entity has been known by a number of names, at present the most widely accepted is that of autoimmune chronic pancreatitis (ACP). The present report describes the clinical, immunological, morphological, functional and pathological characteristics of two patients recently studied at our unit and discusses currently used diagnostic tests. The two patients had a complete response to steroid therapy. In our opinion, ACP is probably underdiagnosed in Spain. The availability of morphological, pathological and serological diagnostic tools developed in recent years will help to precisely determine the epidemiology of this process. Thus, quantification of serum levels of anti-carbonic anhydrase II and IgG4 has greatly contributed to the diagnosis of ACP. These tests should be performed in patients with a possible diagnosis of ACP, those suffering from diabetes mellitus type I with impairment of exocrine function, and those with alcoholic pancreatitis and a poor response to alcohol elimination. Once we are able to diagnose and determine the real prevalence of ACP in our setting, the most appropriate therapy and prognosis of this disease can be established.