This paper compares demographic, morphological, functional, and risk factors between isolated and familial forms of microtia in Ecuadorian mestizo patients. The authors did an epidemiological, and retrospective study with 112 patients divided into isolated microtia (n = 91) and familial microtia (n = 21). Patients with syndromic microtia were not included. In isolated microtia, the mean age was 11.80 ± 16.9, and the most prevalent age group was from 5 to 9 years, with 45.0%; males were 58.2%, and 91.2% of patients were born in a city above 2500 meters about sea level. In familial microtia, the mean age was 15.57 ± 17.2. There were no statistically significant differences between the analyzed variables. In isolated microtia, 41.8% of patients had bilateral involvement, 40.7% had grade 1 microtia in the right ear (RE), and grade 1 in the left ear was 47.3%; external auditory canal atresia of RE was present in 62.6%, and in left ear in 31.6%. External auditory canal atresia sidedness was mostly unilateral in both groups. Most patients did not have tags or pits (78% and 81% in RE and 85.7% and 71.4%). Most patients had moderate hearing loss in both ears. The authors found an association between both microtia forms with external auditory canal atresia in RE; only 20% of patients had unilateral auricular tags or pits in both groups. The authors also found a high incidence (18.75%) of familial microtia, which suggests a distinct pathological genetic component than the more prevalent isolated cases. The authors found a high association of microtia cases from the Ecuadorian highlands above 2500 meters about sea level (over 90%). The presence of "social" intake of alcohol during pregnancy showed over twice the chance of having a child born with microtia.