The study was carried out in the Web Valley of the Bale Moulltaills National Park, Ethiopiarnfrom November 2001 to October 2002. The study focused on the ecology of domestic dogrn(Canis familiaris) to determine the potelllial effects of the domestic dog on the elldemic andrnendangered Ethiopian wolf (Canis simensis) by exploitative and intelference competitioll,rndisease transmition and hybridization. An exam illation of the functional significance of therndogs was also cari'ied out. The density of dogs reached 10 dogslkm2 in wet season andrndecreased to 4 dogslkn? in the {by seasoll. All dogs were oWlled and no feral dog populationrnwas assessed. Nocturnal observation of behaviour of dogs and questionnaire sl/lvey revealedrnthat dogs help the local people in defellding their livestock from wild carnivores. Dogs alsorngave sell'ice by cleaning the area from humallfaeces and carcass. The pastoral people of thernstudy area are in conflict with wild carnivores that depredated on their livestock. Spottedrnhyaena (Crocuta crocuta) was the most serious predator that did 57% of the 704 livestockrndepredated by wild carnivores in the last three years. Leopard (Felis pardus), Common jackalrn(Callis aureus) and Selval cat (Felis serval) cOlltributed 18%, 17% and 9% of the kills,rnrespectively. From a loss of potelltial revenue due to wild camivores' depredatioll onrnlivestock over the past three years, hyella caused 83.5% of the total loss amountillg to US$rn13,102. Comlllon jackal, leopard alld Selval cat cOlllributed, 7.7%, 6.3% and 2.5% of thernloss, respectively. In the study of diets of dogs durillg the focal watch, barely husks andrnhumallfaeces cover larger proportion oftheirfood by contributing 45.03% and 20.68% of therntotal 382 recorded meals respectively. Rock hyrax, rodent and starks hare contributed 4.97%,rn4.19% and 0.26% of the meals, respectively. Cheese and milk, KnipilOfia, carcass and potatorncontributed 8.12%, 6.54%, 5.25% and 3.93%, respectively. From domestic dog faecalrnanalysis, barely husks, human faeces and carcass occurred in 86.83%, 21.42% and 19.42% ofrnthe total 1200 faecals. Next to carcass, potato was the most frequently occurred food item,rn5.25% of the feacals. Remains of grass, rodent and rock hyrax follow potato by contributingrn3.07%, 2.75% and 1.75% of the feacals. Both faecal analyses and focal watch reveal thatrnrodents cOlllribute only a vel)' small proportion of the diet of dogs. As Ethiopian wolves fedrnalmost exclusively on rodent year round, 110 sigllificalll exploitative competition between dogsrnand wolves were assessed by during this study. From line transect and field obselvatioll, onlyrna small proportion of dogs were found to roam out of settlements and most of them roam 011rnmountain tops to hunt on rock hyrax rather than Ethiopian wolf range. Ollly 3% of a total dogrnpopulation were seen roaming ill the Ethiopiall wolf rallge, which are familiar with wolf;rngreet and hUllt side by side without showing allY aggressive behaviour. III such a case, there isrnlittle intelferellce competition between Ethiopian wolf and domestic dogs. However, suchrnclose contact has a risk of hybridization. At present, the more likely threat that dogs pose 011rnEthiopian wolf is disease transmitioll. III the 33 dog-wolf interactions observed amollg nOllrn"roaming dogs" alld wolves that are not familiar to each other, to dominate the illteractiollrndepellds upon the Ilumber ofparticipallts. The numbers of seasonal dogs ill creased by 37% atrnthe end of the year and settlements were continuously pushing the Ethiopian wolf rallge.rnThese two factors are likely to cause serious threat to the survival of the Ethiopiall wolves byrnilltelference competitioll ill the Ilearfuture. Settlement in the 'park' should be minimised.