The structure of dark matter haloes in dwarf galaxies is explored, revealing that they follow a universal density profile. Observations indicate flat central density profiles, conflicting with predictions from cold dark matter (CDM) simulations which suggest cuspy profiles. However, dwarf spiral galaxies, dominated by dark matter, show density profiles consistent with a self-similar, modified isothermal model. This model, described by the equation ρ(r) = ρ₀/(1 + r²/r₀²), fits observed data and suggests that dark matter haloes have a single free parameter, r₀, which determines their structure. Scaling relations between the rotational velocity v₀, the total dark matter mass M₀ inside r₀, and the central density ρ₀ are derived. These relations show that the density profiles depend only on r₀, and that the observed universal mass profiles can be explained by the standard CDM model if all haloes formed from density fluctuations with the same primordial amplitude. The results suggest that the flat cores of dark matter haloes are not formed by subsequent dynamical processes but provide insights into the nature of dark matter. The scaling relations are compared to the Tully-Fisher relation, though they differ in that they relate DM mass to rotational velocity rather than luminosity. These relations can be used to determine distances to DM-dominated dwarf galaxies if their HI-rotation curves are known up to r₀. Cosmological models predict self-similar haloes, but numerical simulations show discrepancies with observations. Possible explanations involve dynamical processes in the baryonic component affecting the DM density profile. However, the observed flat cores are more likely due to the collisionless formation history of dark matter, with constraints on phase space density leading to finite central densities. The nature of dark matter and the origin of finite central density haloes remain poorly understood, highlighting the need for further research.The structure of dark matter haloes in dwarf galaxies is explored, revealing that they follow a universal density profile. Observations indicate flat central density profiles, conflicting with predictions from cold dark matter (CDM) simulations which suggest cuspy profiles. However, dwarf spiral galaxies, dominated by dark matter, show density profiles consistent with a self-similar, modified isothermal model. This model, described by the equation ρ(r) = ρ₀/(1 + r²/r₀²), fits observed data and suggests that dark matter haloes have a single free parameter, r₀, which determines their structure. Scaling relations between the rotational velocity v₀, the total dark matter mass M₀ inside r₀, and the central density ρ₀ are derived. These relations show that the density profiles depend only on r₀, and that the observed universal mass profiles can be explained by the standard CDM model if all haloes formed from density fluctuations with the same primordial amplitude. The results suggest that the flat cores of dark matter haloes are not formed by subsequent dynamical processes but provide insights into the nature of dark matter. The scaling relations are compared to the Tully-Fisher relation, though they differ in that they relate DM mass to rotational velocity rather than luminosity. These relations can be used to determine distances to DM-dominated dwarf galaxies if their HI-rotation curves are known up to r₀. Cosmological models predict self-similar haloes, but numerical simulations show discrepancies with observations. Possible explanations involve dynamical processes in the baryonic component affecting the DM density profile. However, the observed flat cores are more likely due to the collisionless formation history of dark matter, with constraints on phase space density leading to finite central densities. The nature of dark matter and the origin of finite central density haloes remain poorly understood, highlighting the need for further research.