Experimentally determined data to examine the creep behavior of an immature carbonate-rich Posidonia shale (Dottenhausen), subjected to constant stress conditions at temperatures between 50 and 200 °C and confining pressures of 50–200 MPa, simulating elevated in-situ depth conditions. The data are described in and supplementary material to Rybacki et al. (2017; http://doi.org/10.1007/s00603-017-1295-y).The data refer to Figure 1 and Table 1 of Rybacki et al. (2017) and are povided in tab-separated ASCII-Format (.dat). The first column represents time in sec and second column the associated axial strain (decimal separator is a comma). An empty line separates data before and after achieving constant stress conditions (cf., Fig. 1 in Rybacki et al., 2017). The following files are included in Rybacki-et-al_2018-001_data.zip: Sample / (confining) Pressure [MPa] / Temperature [°C] / (axial differential) Stress [MPa] / comments: DOT01 / 50 / 100 / 166 DOT02 / 50 / 100 / 150 DOT03 / 50 / 100 / 157 DOT04 / 50 / 100 / 148 / (missing stran values in the upper c. 22.5 sec)DOT09 / 100 / 100 / 169DOT101 / 100 / 100 / 111DOT103 / 100 / 100 / 152DOT104 / 50 / 100 / 154DOT105 / 150 / 100 / 154DOT107 / 100 / 200 / 113 DOT108 / 100 / 200 / 61DOT110 / 100 / 50 / 110