"The significant correlation between infrastructure and economic productivity mirrors ñ especially in times of required global competitiveness ñ the importance as well as the fundamental role of this sector. In recent years, private investment in infrastructure ñ direct as well as indirect ñ has significantly increased. This has been mainly caused by a financial strain on governments, making them unable to provide adequate infrastructure provision. Considering the current financial and economic crisis, the aspect of infrastructure investment might gain even more weight what is due to governmental funding programmes all over the world. Therefore, this paper aims to establish a descriptional and definitional framework of infrastructure as well as a classification of infrastructure within the asset class real estate. Moreover, the importance of infrastructure in an economic context, based on existing literature, is reconsidered. In the analytical part of this study, time series data of total infrastructure returns are incorporated into an asset allocation model which is based on a meanñlower partial moment approach instead of a ìusualî meanñvariance optimization algorithm. This asset allocation model aims to derive the optimal proportion of infrastructure within a multi asset portfolio consisting of equities, government bonds, T-bills as well as direct and indirect real estate. Comparing obtained portfolio allocations should reveal the difference between real estate and infrastructure regarding their optimal portfolio weights and might constitute an indicator if infrastructure depicts a useful extension for institutional investors within their multi asset portfolios.""