Background
Nearly all Twin Registers are based in developed countries and there is no Twin Register in the developing world.

Objectives
To initiate the process of establishing a nation-wide Twin Register in Sri Lanka by starting a volunteer register first and working towards a population based register.

Methods
Regular news paper adevertisements, feature articles, radio talks, and television programs were used to publicise a competition for twins, their parents/relatives and friends requesting them to participate by sending in details of twins. Comptetition took place from 28/3/97 for a period of 3 months. It offered prices for 3 winners selected by drawing lots. Advertisements highlighted the objective of the competition as establishing a twin register for future research and emphasised that informed consent would be obtained for individual research projects. Although others have previously used media publicity to enroll twins in twin registers, to the best of our knowledge this is the first time that a competition was used.

Results
4374 Twin Pairs (Same Sex: male 1327, Female 1610, Different Sex 1118, Sex to be verified 321); 80 Triplets (Same Sex: Male 16, Female 24. Different Sex 39, Sex to be verified 1) and 2 Quadruplets (Different Sex) have registered. The oldest Twins, Triplets, Quadruplets are 80, 46, and 5 years old respectively. 75% of Twins, 85% of Triplets, and all quadruplets are less than 25 years old. Zygosity determination will be done shortly using the questionnaire method. This will be followed by several projects.

Conclusions
Establishing a Twin Register for research purposes is possible in a developing country.