The aims 0 1' t his study we re to evaluate proliferative and apoptotic cell distribution pattern in condylar articu lar and pl'oliferative layer as two types of diet(soft and ha rd) we1'e supplied to growing 1'a ts, 30 male Sprague Dawley g1'owing l'ats(twenty-one c1ays fl'om bi l'th) were c1ivided into two group, Each 15 rats were supplied by soft and hal'd di et , After c1 iluted Bl'du solution(5mg/ Kg)was injected into pel'itoneum befol'c sacrificc. rats wel'e sacl'i f iced at 1. 2. 3 week llltel'vals St1'eptoavidin-Biotin method for Brdu was used to evaluate celluJar proliferative activity. ancl fluol'escent TUNEL method was used to estima te the apoptotic activity, The results about this expe riment wel'e recorded about ante1'io1' and posterior condyle separateJy, In anteriol' portion of condyle, soft diet group showed inc1'eased p1'olife1'ative celluJar activity tha n hal'd diet group dw'ing 1, 2 week but decl'eased than hal'd diet g1'oup at 3 weeks. while hal'd diet group showed constant p1'oliferative cellular activity during all experimenta l period , ln posterior pOl'tion of condyl e、soft diet group showed increased activity than hard diet group at 3 weeks, while ha rd di et gl'oup showed constant proliferative cellular activity during exper‘ imental period , In a nterior pOl'tion of condyle‘ soft c1 iet group showed increased apoptotic activity with time progress, but hard diet group showed continuous low level of activity during experimental period , In posterio1' porti on 0 1' condyle, hard diet group showed cons tant low level apoptotic activity, plthough showed the lowes t leveJ at 1 week, On the con trary soft diet g1'oup showed c1ecl'eased apoptotic activity wi th time progress, ConcJusively, in soft diet group an teroposterior direction was reduced in condyJar morphologic dimension because of decreased prol iferative cellular and increased apoptotic activity on anterior portion and vertical dimension 0 1' condyle was increased because of increased proliferative cellular and decreased apoptotic activity on posterior portion. but in hard di et group proli ferative cellular and apoptotic activity were comparatively constant. and thus harcl diet group s howed antet'opos teriorJy broad and flat condylar morphoJogy