A study investigating the spatial and temporal variation of physiochemical parameters in headwater streams was performed over a period of 12 months in the catchment of the Kamienna Creek (northern Poland). Water samples were collected in monthly cycles along three streams (in their upper, middle and lower sections) flowing through the riparian forest, as well as from the Kamienna Creek. In the collected samples, parameters including temperature, pH, electrolytic conductivity, concentration of dissolved oxygen and K⁺, Na⁺, Ca²⁺, Mg²⁺, NH₄⁺, HCO₃^-, Cl^-, NO₃^-, PO₄^3- and SO₄^2- ions were determined. The collected water samples were characterised by a neutral or slightly basic pH (6.6-8.9), as well as considerable variation in average electrolytic conductivity, with values ranging between 213 and 544 μS.cm^-3 in streams and between 114 and 366 μS.cm^-3 in the creek. In general, waters were characterised by low concentrations of dissolved compounds, with a predominance of  HCO₃^- and Ca²⁺. The waters in both the streams and the creek are calcium-bicarbonate type and are characterised by low seasonal variability, with season having no influence on concentrations of Ca²⁺, Mg²⁺ and HCO₃^-, nor on conductivity, hardness and mineralisation. However, spatial variation in the chemical composition of waters was observed. Based on data analysis it was found that whereas the waters of the Kamienna Creek were dominated by Ca²⁺/Mg²⁺ and HCO₃^-, those the water of streams were characterised by moderate and low concentrations of calcium, magnesium and hydrocarbonate ions.