Since the appearance, in the early eighties, of first publications describing plasma source mass spectrometry as a viable analytical technique, there has been a rapid increase in the number of papers detailing its possible applications, instrumental developments and fundamental studies. In the laboratories involved in the environmental or food monitoring problematics, inductively coupled plasma-mass spectrometry (ICP-MS) systems are usually acquired in order to analyze large series of samples. At our knowledge, very rare are works dedicated to the sum of factors and additional problems usually encountered in the routine analysis using this analytical technique. In this work, we will try to fill in these gaps by discussing the main factors that may strongly influence the analysis of large series of samples. Firstly, there are uncertainties associated to the choice of measurement parameters: calibration blanks, curve algorithms and their long-term validity, selection of internal standards, recalibration blocks and usefulness of correction equations. Secondly, we will discuss analytical parameters that concern samples themselves: their appropriate dilution and acidification as well as the knowledge of matrix effects possibly produced. Finally, there is also a very important point concerning appropriate definition of the procedure blank as well as its utilization. Only the careful consideration of all these aspects permits to obtain accurate results during routine analysis. Aim of this work is not oriented to discussion of typical and well-documented ICP-MS individual problems but rather to means that allow to overcome main uncertainties resulting in an improvement of the whole routine analysis.