The interfacial chemistry between alginic acid and a titanium surface has been examined using x-ray photoelectron spectroscopy (XPS). This study is motivated by the effort to mitigate effects of seawater biofouling on heat transfer surfaces via materials or surface modification strategies. Alginic acid is a predominant adhesive in bacterial biofilms, and titanium is a common material in naval ship cooling and piping systems. XPS has been used to quantify the alginic acid adsorbed to the titanium surface from aqueous solution. The experiments were performed at various solution pH's to examine the effect on alginic acid adsorption of changing the charge state of the ionizable groups on the alginic acid and of the titanium surface. The effects of ions in the solution were investigated by performing the alginic acid adsorption in the presence of calcium chloride. To separate the effects of the carboxyl and hydroxyl moieties present in alginic acid, XPS has also been used to measure caproic acid (carboxyl) and glucose (hydroxyl) adsorption as a function of solution pH. High-resolution XPS spectra have been utilized to separate the various carbon and oxygen chemistries present, and angle-resolved XPS spectra and advancing contact angle measurements were used to elucidate molecular orientation effects. Atomic force microscope (AFM) images were obtained to determine adsorbate morphology and surface coverage. These data will be interpreted in light of potential alginic acid - titanium adsorption mechanisms such as hydrogen bonding and anion exchange. This information regarding the biofilm-surface chemical interaction will be useful in developing fouling resistant surfaces. The NSWC Carderock Division In-House Laboratory Independent Research Program supported this work.