This paper introduces the recent state of research on creep of new concrete made by montmorillonite mineral nano particles (MNP) and then comparing them with control specimens made from reference concrete. Concrete compositions with unconventional additives were designed and prepared. Standard sample cubes 100x100x100 mm and prisms 40x40x160 mm were produced in order to investigate the mechanical characteristics of the material. Experimental studies review new concrete compositions on long – term deformations (creep). The samples were put into a creep lever test stand and loaded (see Figure 1). The constant compressive load was equal to 30% of the maximum strength of the concrete. Stress levels were calculated from compression strength results. At the beginning of the test, the samples were 51 and 63 days old and they were kept under constant load for 90 days and for recoverable creep they were kept without load for 40 days. Specimens were tested in two extreme environments: in one case there was 100% humidity provided by protecting the specimens from desiccation and in the other case specimens were air-dried and protected from any moisture. Concrete specimens were subject to load in a constant room temperature and with a constant level of moisture. The investigated properties include compression strength, modulus of elasticity and creep. A number of experimental results are presented in Figure 2. This experimental study proves that montmorillonite nano particles in small dosage (8 kg in m3) don't have negative influence on mechanical and deformation characteristics of concrete. Some positive effects are established. Concrete mix containing montmorillonite nano particles perform long-term hardening effect. MNP concrete specimens cured in dry conditions showed larger increase of basic creep deformations than reference concrete specimens, but for samples hardened in moist conditions the values of basic creep deformation were similar. In the future, the physical and mechanical properties of new high-strength concrete containing montmorillonite nano particles as an alternative admixture should be investigated in a more detailed way.