A sample rack for holding sample tubes in a single row includes an angle shaped frame formed by a longitudinally extending vertical rear wall and a horizontal top wall. The top wall includes a plurality of sample tube openings. A plurality of vertical partitions are joined to the angle shaped frame in spaced arrangement to define sample tube chambers for receiving sample tubes. At least one front vertical connecting section connects the bottom portions of two adjacent partitions opposite the rear wall. A leaf spring device is attached to the connecting section. The leaf spring device includes a support section and a plurality of arms opposite the rear wall extending upwardly from the support section into the sample tube chambers.