The concentrations of the metalsCu, Pb, Mn and Zn in fra ctions geochemistry insix sediment core of the lagoon Unare, Venezuela.A procedure of sequential extraction of metalswas determined, for each fraction was usedreagents different and conditions of digestionand the concentrations of metals determinedwith spectrophotometer of Atomic Absorption.The fractionating of metals indicated an order ofdecreasing concentration as it follows: residualfraction > organic/sulfur matter > carbonates>interchangeable. The metals displayed valuesin the reactive phase between : n.d-7,90; 0,00-4,90; 133,95-961 ,79 and 0,05-9,61 IJg /g for Cu,Pb, Mn and Zn, respectively; being observedin most of the core an increase in the superiorlayers caused by diagenetics processes,changes in the textural composition (containedof clay or organic matter) due to the anthropicscontributions that the lagoon receives. The Mnpresented in core 1, 2 and 3 the smaller concentrationsto the surface, which suggests analteration of the natural geochemical cycles thattends to a diminution of the manganese contributionsthrough tlíe time. In the Zn, its verticaldistribution reflects a strong relation between themetal, the organic matter and texture in relationto the depth, which is of sandy and poor texturein organic matter, with a contained minor of th ismetal. The concentrations average of metalstotal are were: 36,31; 7,57; 445,60 and 64.07IJg/g for Cu, Pb, Mn and Zn respectively. Theseresults are analogous to the reported ones forsediments no contaminated; nevertheless, somemetals in the reactive phase, showed to slightincreases towards the surface, indicating recentcontamination, product of the intervention thathas undergone this lagoon in the last decadesand to the contributions of the Unare river.