This paper examines the relationship between portofolio risk and the number of money in a diversified portofolio of Indonesia money in Money Market. The periode between januari 2000 until September 2008. From 15 money, 1 Deposite, 3 Indonesia Bank Sertification, and 1 Syari’ah Indonesia Bank Sertification on 70 percepton time series, Samples is get 283 instrument. These are taken to form sets of portofolios using both the Random Diversification Approach and tha Markowitz Mean-Variance Optimisation Approach. On average, a diversified portofolio of Indonesia stocks contains at least 7 randomly chosen securities, and than if used Markowitz approach, a portofolio of 7 securities is considered a diversified portofolio. The numbers sames with numbers if we used random approach. The result are suitable to the choice of the model specified and the method of estimation used.