Abstract: A tri-axial fluxgate magnetometer and housing therefor that includes elements which facilitate a small sized, relatively low cost magnetometer assembly without sacrificing accuracy and reliability. The assembly includes a unitary sensor substrate capable of orthogonally positioning each of the three fluxgate axes and their respective coils and sensors. The assembly positions the unitary substrate on a circuit board that contains the appropriate harmonic amplifiers, phase detectors, and integrators for signals from each of the three fluxgate axes. A second circuit board positioned parallel to, but apart from, the first, incorporates an appropriate frequency oscillator, frequency divider, and, if necessary, an appropriate voltage regulator. The circuit boards, positioned in parallel as described, are mounted to an end plate that incorporates a signal/control connector and which positions and holds the components of the magnetometer assembly in a generally rectangular configuration.