This paper aims at assessing the relationship between ownership structure, performance and investment activity. In particular it studies how behavioural differences between farms related to ownership structure influence farms' investment activity and thus their further development potential resulting in farm structural changes. The paper analyses a sample of corporate farms over 7 years, 1997-2003, using structural model of three equations including investment accelerator model. This model considers the effect of ownership on (a) technical efficiency as proxy for the quality of operational management, (b) returns on capital as proxy for quality of financial management, (c) investment activity, and (d) investment sensitivity to internal funds as proxy for owners/managers opposition to credit financing. The empirical results provide evidence of a theoretically justifiable positive effect of ownership concentration on investment activity and farms' economic performance, and a theoretically consistent effect of external/employee ownership on technical performance. However, the authors are not able to confirm empirically the theoretically based effect of external/employee ownership on farm investment activity.