Pars planitis is an intraocular inflammatory disorder which usually affects children or young adults and is characterized by vitreous cells and debris ('snowballs'), exudate, and 'snowbank' formation along the pars plana, variable periphlebitis, and cystoid macular edema. Although no inheritance pattern has been defined, familial cases of pars planitis have been reported. This report describes pars planitis in two sisters, one of whom had evidence of demyelinating disease at presentation. The literature on familial pars planitis is reviewed. To the author's knowledge this is the first case of familial pars planitis as the presenting sign of possible demyelinating disease.