The significance of measurement in characterization of bio-materials such as leaves, seeds, fruits, wood, animal products to mention but few, cannot be overemphasized. More so, calibration of agricultural related machinery is essential for optimum production. This book is aimed at familiarizing students who are studying agricultural related disciplines with basic instruments in the field of agriculture as well as the principle of operations such instruments. Here, the interest of students in application of instruments is developed. Instruments that are utilized in the agricultural workshop, soil and water engineering, post-harvest and pre-harvest operations were treated in this book.The author wish to express his sincere gratitude to students of the Department of Agricultural and Bio-Environmental Engineering, Federal College of Forestry Mechanisation for their interest in application of instruments in agricultural related activities in the course of their studies. I also want thank the present and previous Provosts of the college for creating conducive and enabling environment for this course.Fadele, O.K.