An illumination apparatus is attachable to surgical instruments, and provides illumination of the operating field, particularly those requiring good illumination of normally poorly illuminated organ cavities, during surgical procedures. The illumination apparatus includes a light source (1) connected to a power supply (2). The light source (1) and part or all of the power supply source are housed in a casing (3) that has at least one attaching means (5) on its outer surface which is suitable for removably attaching the illumination apparatus to a surgical instrument, and desirably, to several different surgical instruments at various times during a particular surgical procedure. Due to its weight, design and size, the illumination apparatus allows for easy shifting of the illumination apparatus along the surgical instrument without interfering with the normal use of the surgical instruments.
