In this study the evolution of the preferred orientation of diamond layers as a function of the nitrogen content in the gas phase during the growth process is determined using X-ray texture analysis and compared with the morphological structure. Because of the small diameter of the homogeneous area of the diamond films investigated a mono-capillary is used to obtain a small footprint of the X-ray beam on the sample. Phase identification showed the presence of crystalline molybdenum carbide at the interface. The pole figures revealed a change in texture with increasing nitrogen in the gas phase. The role of nitrogen in the growth process is discussed.