Gastrointestinal carcinoid tumors are uncommon neuroendocrine tumours that may be associated with synchronous or metachronous primary tumours of other histological type, most frequently colorectal adenocarcinomas. Primary ovarian mucinous adenocarcinomas have been reported to coincide with few other ovarian tumours and minority of these tumours may occur in association with Lynch syndrome. However association of duodenal carcinoid with ovarian mucinous adenocarcinoma is distinctly unusual and, to our knowledge, has not been previously described. We report a case of occult metastasising duodenal atypical carcinoid that was incidentally detected during surgical intervention performed for left ovarian mucinous cystadenocarcinoma in a middle aged female. The carcinoid tumour was Stage IIIB with regional nodal metastasis and the ovarian tumour was Stage IA with low grade histology.