This paper presents the experimental investigation of a novel sunlight concentrating and optical fibre guiding system for daylighting applications. The key part of the system is a sunlight concentrator unit which includes a novel mirror image co-focus compound parabolic concentrator. The structure and working principle of an experimental sunlight concentrating and optical fibre guiding system are introduced. Under a real sky condition, the experimental system was investigated to determine its performance and characteristics. The relationship curves between the internal illuminance of the integrating box and external illuminance are given for different tracking accuracy values and optical fibre geometries. The transmittance of the experimental system is calculated from the measured illuminance values. The results demonstrate the feasibility of the novel sunlight concentrating and optical fibre guiding system for daylighting applications. (C) 2011 Elsevier Ltd. All rights reserved.